Currently the data needs to be copied twice between sg, tcmu data area and
userspace buffer if backstore holds its own userspace buffer, then we can
use uio ioctl to copy data between sg and userspace buffer directly to
bypass data area to improve performance.
Use tcm_loop and tcmu(backstore is file) to evaluate performance,
fio job: fio -filename=/dev/sdb -direct=1 -size=2G -name=1 -thread
-runtime=60 -time_based -rw=randread -numjobs=16 -iodepth=16 -bs=128k
Without this patch:
READ: bw=3539MiB/s (3711MB/s), 207MiB/s-233MiB/s (217MB/s-244MB/s),
io=104GiB (111GB), run=30001-30002msec
With this patch:
READ: bw=4420MiB/s (4634MB/s), 274MiB/s-278MiB/s (287MB/s-291MB/s),
io=259GiB (278GB), run=60001-60002msec
Reviewed-by: Xiaoguang Wang <[email protected]>
Signed-off-by: Guixin Liu <[email protected]>
---
drivers/target/target_core_user.c | 171 +++++++++++++++++++++++++++++-----
include/uapi/linux/target_core_user.h | 9 ++
2 files changed, 157 insertions(+), 23 deletions(-)
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 7b2a89a..afea088 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -122,6 +122,7 @@ struct tcmu_dev {
#define TCMU_DEV_BIT_BLOCKED 2
#define TCMU_DEV_BIT_TMR_NOTIFY 3
#define TCMU_DEV_BIT_PLUGGED 4
+#define TCMU_DEV_BIT_BYPASS_DATA_AREA 5
unsigned long flags;
struct uio_info uio_info;
@@ -642,12 +643,17 @@ static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
tcmu_cmd->se_cmd = se_cmd;
tcmu_cmd->tcmu_dev = udev;
- tcmu_cmd_set_block_cnts(tcmu_cmd);
- tcmu_cmd->dbi = kcalloc(tcmu_cmd->dbi_cnt, sizeof(uint32_t),
- GFP_NOIO);
- if (!tcmu_cmd->dbi) {
- kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
- return NULL;
+ if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags)) {
+ tcmu_cmd_set_block_cnts(tcmu_cmd);
+ tcmu_cmd->dbi = kcalloc(tcmu_cmd->dbi_cnt, sizeof(uint32_t),
+ GFP_NOIO);
+ if (!tcmu_cmd->dbi) {
+ kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
+ return NULL;
+ }
+ } else {
+ tcmu_cmd->dbi_cnt = 0;
+ tcmu_cmd->dbi = NULL;
}
return tcmu_cmd;
@@ -1093,16 +1099,18 @@ static int queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, sense_reason_t *scsi_err)
tcmu_cmd_reset_dbi_cur(tcmu_cmd);
iov = &entry->req.iov[0];
- if (se_cmd->data_direction == DMA_TO_DEVICE ||
- se_cmd->se_cmd_flags & SCF_BIDI)
- scatter_data_area(udev, tcmu_cmd, &iov);
- else
- tcmu_setup_iovs(udev, tcmu_cmd, &iov, se_cmd->data_length);
-
+ if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags)) {
+ if (se_cmd->data_direction == DMA_TO_DEVICE ||
+ se_cmd->se_cmd_flags & SCF_BIDI)
+ scatter_data_area(udev, tcmu_cmd, &iov);
+ else
+ tcmu_setup_iovs(udev, tcmu_cmd, &iov, se_cmd->data_length);
+ }
entry->req.iov_cnt = iov_cnt - iov_bidi_cnt;
/* Handle BIDI commands */
- if (se_cmd->se_cmd_flags & SCF_BIDI) {
+ if ((se_cmd->se_cmd_flags & SCF_BIDI)
+ && !test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags)) {
iov++;
tcmu_setup_iovs(udev, tcmu_cmd, &iov, tcmu_cmd->data_len_bidi);
entry->req.iov_bidi_cnt = iov_bidi_cnt;
@@ -1366,16 +1374,19 @@ static bool tcmu_handle_completion(struct tcmu_cmd *cmd,
else
se_cmd->se_cmd_flags |= SCF_TREAT_READ_AS_NORMAL;
}
- if (se_cmd->se_cmd_flags & SCF_BIDI) {
- /* Get Data-In buffer before clean up */
- gather_data_area(udev, cmd, true, read_len);
- } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
- gather_data_area(udev, cmd, false, read_len);
- } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
- /* TODO: */
- } else if (se_cmd->data_direction != DMA_NONE) {
- pr_warn("TCMU: data direction was %d!\n",
- se_cmd->data_direction);
+
+ if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags)) {
+ if (se_cmd->se_cmd_flags & SCF_BIDI) {
+ /* Get Data-In buffer before clean up */
+ gather_data_area(udev, cmd, true, read_len);
+ } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
+ gather_data_area(udev, cmd, false, read_len);
+ } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
+ /* TODO: */
+ } else if (se_cmd->data_direction != DMA_NONE) {
+ pr_warn("TCMU: data direction was %d!\n",
+ se_cmd->data_direction);
+ }
}
done:
@@ -1973,6 +1984,84 @@ static int tcmu_release(struct uio_info *info, struct inode *inode)
return 0;
}
+long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
+ struct iovec __user *uiovec,
+ unsigned long vcnt,
+ bool is_copy_to_sgl)
+{
+ struct iovec iovstack[UIO_FASTIOV];
+ struct iovec *iov = iovstack;
+ struct iov_iter iter;
+ ssize_t ret;
+ struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
+ struct scatterlist *data_sg, *sg;
+ int i;
+ unsigned int data_nents;
+ long copy_ret = 0;
+
+ if (se_cmd->se_cmd_flags & SCF_BIDI) {
+ data_sg = se_cmd->t_bidi_data_sg;
+ data_nents = se_cmd->t_bidi_data_nents;
+ } else {
+ data_sg = se_cmd->t_data_sg;
+ data_nents = se_cmd->t_data_nents;
+ }
+
+ ret = import_iovec(READ, uiovec, vcnt, ARRAY_SIZE(iovstack), &iov, &iter);
+ if (ret < 0) {
+ pr_err("import iovec failed.\n");
+ return -EFAULT;
+ }
+
+ for_each_sg(data_sg, sg, data_nents, i) {
+ if (is_copy_to_sgl)
+ ret = copy_page_from_iter(sg_page(sg), sg->offset, sg->length, &iter);
+ else
+ ret = copy_page_to_iter(sg_page(sg), sg->offset, sg->length, &iter);
+ if (ret < 0) {
+ pr_err("copy failed.\n");
+ copy_ret = -EFAULT;
+ break;
+ }
+ }
+ kfree(iov);
+ return copy_ret;
+}
+
+long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
+{
+ struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
+ struct tcmu_data_xfer __user *uxfer = (struct tcmu_data_xfer __user *)arg;
+ struct tcmu_data_xfer xfer;
+ struct tcmu_cmd *tcmu_cmd;
+
+ if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags))
+ return -EINVAL;
+
+ if (copy_from_user(&xfer, uxfer, sizeof(xfer)))
+ return -EFAULT;
+
+ tcmu_cmd = xa_load(&udev->commands, xfer.cmd_id);
+ if (!tcmu_cmd) {
+ set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
+ return -EFAULT;
+ }
+
+ if (test_bit(TCMU_CMD_BIT_EXPIRED, &tcmu_cmd->flags))
+ return -EFAULT;
+
+ switch (cmd) {
+ case TCMU_IOCTL_CMD_COPY_TO_SGL:
+ return tcmu_ioctl_copy_between_sgl_and_iovec(tcmu_cmd, xfer.iovec,
+ xfer.iov_cnt, true);
+ case TCMU_IOCTL_CMD_COPY_FROM_SGL:
+ return tcmu_ioctl_copy_between_sgl_and_iovec(tcmu_cmd, xfer.iovec,
+ xfer.iov_cnt, false);
+ default:
+ return -EINVAL;
+ }
+}
+
static int tcmu_init_genl_cmd_reply(struct tcmu_dev *udev, int cmd)
{
struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
@@ -2230,6 +2319,7 @@ static int tcmu_configure_device(struct se_device *dev)
info->mmap = tcmu_mmap;
info->open = tcmu_open;
info->release = tcmu_release;
+ info->ioctl = tcmu_ioctl;
ret = uio_register_device(tcmu_root_device, info);
if (ret)
@@ -2838,6 +2928,40 @@ static ssize_t tcmu_nl_reply_supported_store(struct config_item *item,
}
CONFIGFS_ATTR(tcmu_, nl_reply_supported);
+static ssize_t tcmu_bypass_data_area_show(struct config_item *item, char *page)
+{
+ struct se_dev_attrib *da = container_of(to_config_group(item),
+ struct se_dev_attrib, da_group);
+ struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
+
+ if (test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags))
+ return snprintf(page, PAGE_SIZE, "%s\n", "true");
+ else
+ return snprintf(page, PAGE_SIZE, "%s\n", "false");
+}
+
+static ssize_t tcmu_bypass_data_area_store(struct config_item *item, const char *page,
+ size_t count)
+{
+ struct se_dev_attrib *da = container_of(to_config_group(item),
+ struct se_dev_attrib, da_group);
+ struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
+ bool bypass_data_area;
+ int ret;
+
+ ret = strtobool(page, &bypass_data_area);
+ if (ret < 0)
+ return ret;
+
+ if (bypass_data_area)
+ set_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags);
+ else
+ clear_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags);
+
+ return count;
+}
+CONFIGFS_ATTR(tcmu_, bypass_data_area);
+
static ssize_t tcmu_emulate_write_cache_show(struct config_item *item,
char *page)
{
@@ -3069,6 +3193,7 @@ static ssize_t tcmu_free_kept_buf_store(struct config_item *item, const char *pa
&tcmu_attr_emulate_write_cache,
&tcmu_attr_tmr_notification,
&tcmu_attr_nl_reply_supported,
+ &tcmu_attr_bypass_data_area,
NULL,
};
diff --git a/include/uapi/linux/target_core_user.h b/include/uapi/linux/target_core_user.h
index 27ace51..c02a45e 100644
--- a/include/uapi/linux/target_core_user.h
+++ b/include/uapi/linux/target_core_user.h
@@ -185,4 +185,13 @@ enum tcmu_genl_attr {
};
#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
+struct tcmu_data_xfer {
+ unsigned short cmd_id;
+ unsigned long iov_cnt;
+ struct iovec __user *iovec;
+};
+
+#define TCMU_IOCTL_CMD_COPY_TO_SGL _IOW('T', 0xe0, struct tcmu_data_xfer)
+#define TCMU_IOCTL_CMD_COPY_FROM_SGL _IOW('T', 0xe1, struct tcmu_data_xfer)
+
#endif
--
1.8.3.1
Hi Guixin,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on mkp-scsi/for-next linux/master linus/master v5.17-rc4 next-20220216]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Guixin-Liu/uio-add-ioctl-to-uio/20220217-103120
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git e6cb9c167eeb8f90ab924666c573e69e85e700a0
config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20220217/[email protected]/config)
compiler: arceb-elf-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/c604d03c2be8ca4b3533bb151bcd2d10379debff
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Guixin-Liu/uio-add-ioctl-to-uio/20220217-103120
git checkout c604d03c2be8ca4b3533bb151bcd2d10379debff
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arc SHELL=/bin/bash drivers/target/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> drivers/target/target_core_user.c:1987:6: warning: no previous prototype for 'tcmu_ioctl_copy_between_sgl_and_iovec' [-Wmissing-prototypes]
1987 | long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/target/target_core_user.c:2031:6: warning: no previous prototype for 'tcmu_ioctl' [-Wmissing-prototypes]
2031 | long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
| ^~~~~~~~~~
vim +/tcmu_ioctl_copy_between_sgl_and_iovec +1987 drivers/target/target_core_user.c
1986
> 1987 long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
1988 struct iovec __user *uiovec,
1989 unsigned long vcnt,
1990 bool is_copy_to_sgl)
1991 {
1992 struct iovec iovstack[UIO_FASTIOV];
1993 struct iovec *iov = iovstack;
1994 struct iov_iter iter;
1995 ssize_t ret;
1996 struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
1997 struct scatterlist *data_sg, *sg;
1998 int i;
1999 unsigned int data_nents;
2000 long copy_ret = 0;
2001
2002 if (se_cmd->se_cmd_flags & SCF_BIDI) {
2003 data_sg = se_cmd->t_bidi_data_sg;
2004 data_nents = se_cmd->t_bidi_data_nents;
2005 } else {
2006 data_sg = se_cmd->t_data_sg;
2007 data_nents = se_cmd->t_data_nents;
2008 }
2009
2010 ret = import_iovec(READ, uiovec, vcnt, ARRAY_SIZE(iovstack), &iov, &iter);
2011 if (ret < 0) {
2012 pr_err("import iovec failed.\n");
2013 return -EFAULT;
2014 }
2015
2016 for_each_sg(data_sg, sg, data_nents, i) {
2017 if (is_copy_to_sgl)
2018 ret = copy_page_from_iter(sg_page(sg), sg->offset, sg->length, &iter);
2019 else
2020 ret = copy_page_to_iter(sg_page(sg), sg->offset, sg->length, &iter);
2021 if (ret < 0) {
2022 pr_err("copy failed.\n");
2023 copy_ret = -EFAULT;
2024 break;
2025 }
2026 }
2027 kfree(iov);
2028 return copy_ret;
2029 }
2030
> 2031 long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
2032 {
2033 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
2034 struct tcmu_data_xfer __user *uxfer = (struct tcmu_data_xfer __user *)arg;
2035 struct tcmu_data_xfer xfer;
2036 struct tcmu_cmd *tcmu_cmd;
2037
2038 if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags))
2039 return -EINVAL;
2040
2041 if (copy_from_user(&xfer, uxfer, sizeof(xfer)))
2042 return -EFAULT;
2043
2044 tcmu_cmd = xa_load(&udev->commands, xfer.cmd_id);
2045 if (!tcmu_cmd) {
2046 set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
2047 return -EFAULT;
2048 }
2049
2050 if (test_bit(TCMU_CMD_BIT_EXPIRED, &tcmu_cmd->flags))
2051 return -EFAULT;
2052
2053 switch (cmd) {
2054 case TCMU_IOCTL_CMD_COPY_TO_SGL:
2055 return tcmu_ioctl_copy_between_sgl_and_iovec(tcmu_cmd, xfer.iovec,
2056 xfer.iov_cnt, true);
2057 case TCMU_IOCTL_CMD_COPY_FROM_SGL:
2058 return tcmu_ioctl_copy_between_sgl_and_iovec(tcmu_cmd, xfer.iovec,
2059 xfer.iov_cnt, false);
2060 default:
2061 return -EINVAL;
2062 }
2063 }
2064
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
hi,
> On Thu, Feb 17, 2022 at 10:29:22AM +0800, Guixin Liu wrote:
>> --- a/include/uapi/linux/target_core_user.h
>> +++ b/include/uapi/linux/target_core_user.h
>> @@ -185,4 +185,13 @@ enum tcmu_genl_attr {
>> };
>> #define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
>>
>> +struct tcmu_data_xfer {
>> + unsigned short cmd_id;
>> + unsigned long iov_cnt;
>> + struct iovec __user *iovec;
>> +};
> That is no way to define a structure that crosses the user/kernel
> boundry, it just will not work at all, even if we wanted it to :(
Sorry, I don't quite understand your comments well, can you explain more
why this structure
does not work, except that "unsigned short" or "unsigned long" here
isn't correct, should use
u16 or u32.
Syscalls, such as readv/preadv also pass a struct iovec from user to
kernel, thanks.
Regards,
Xiaoguang Wang
>
> sorry,
>
> greg k-h
On Thu, Feb 17, 2022 at 07:13:07PM +0800, Xiaoguang Wang wrote:
> hi,
>
> > On Thu, Feb 17, 2022 at 10:29:22AM +0800, Guixin Liu wrote:
> > > --- a/include/uapi/linux/target_core_user.h
> > > +++ b/include/uapi/linux/target_core_user.h
> > > @@ -185,4 +185,13 @@ enum tcmu_genl_attr {
> > > };
> > > #define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
> > > +struct tcmu_data_xfer {
> > > + unsigned short cmd_id;
> > > + unsigned long iov_cnt;
> > > + struct iovec __user *iovec;
> > > +};
> > That is no way to define a structure that crosses the user/kernel
> > boundry, it just will not work at all, even if we wanted it to :(
> Sorry, I don't quite understand your comments well, can you explain more why
> this structure
> does not work, except that "unsigned short" or "unsigned long" here isn't
> correct, should use
> u16 or u32.
__u32 and __u16 must be used for structures like this. Also it's
unaligned and has a hole in it, and will cause problems with compilers.
You didn't try this on a 32/64bit system either :(
thanks,
greg k-h
Hi Guixin,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on mkp-scsi/for-next linux/master linus/master v5.17-rc4 next-20220216]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Guixin-Liu/uio-add-ioctl-to-uio/20220217-103120
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git e6cb9c167eeb8f90ab924666c573e69e85e700a0
config: i386-randconfig-s002 (https://download.01.org/0day-ci/archive/20220217/[email protected]/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce:
# apt-get install sparse
# sparse version: v0.6.4-dirty
# https://github.com/0day-ci/linux/commit/c604d03c2be8ca4b3533bb151bcd2d10379debff
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Guixin-Liu/uio-add-ioctl-to-uio/20220217-103120
git checkout c604d03c2be8ca4b3533bb151bcd2d10379debff
# save the config file to linux build tree
mkdir build_dir
make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=i386 SHELL=/bin/bash drivers/target/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
sparse warnings: (new ones prefixed by >>)
>> drivers/target/target_core_user.c:1987:6: sparse: sparse: symbol 'tcmu_ioctl_copy_between_sgl_and_iovec' was not declared. Should it be static?
>> drivers/target/target_core_user.c:2031:6: sparse: sparse: symbol 'tcmu_ioctl' was not declared. Should it be static?
Please review and possibly fold the followup patch.
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
Hi Guixin,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on mkp-scsi/for-next linux/master linus/master v5.17-rc4 next-20220216]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Guixin-Liu/uio-add-ioctl-to-uio/20220217-103120
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git e6cb9c167eeb8f90ab924666c573e69e85e700a0
config: riscv-randconfig-r042-20220217 (https://download.01.org/0day-ci/archive/20220217/[email protected]/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 0bad7cb56526f2572c74449fcf97c1fcda42b41d)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv64-linux-gnu
# https://github.com/0day-ci/linux/commit/c604d03c2be8ca4b3533bb151bcd2d10379debff
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Guixin-Liu/uio-add-ioctl-to-uio/20220217-103120
git checkout c604d03c2be8ca4b3533bb151bcd2d10379debff
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash drivers/target/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> drivers/target/target_core_user.c:1987:6: warning: no previous prototype for function 'tcmu_ioctl_copy_between_sgl_and_iovec' [-Wmissing-prototypes]
long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
^
drivers/target/target_core_user.c:1987:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
^
static
>> drivers/target/target_core_user.c:2031:6: warning: no previous prototype for function 'tcmu_ioctl' [-Wmissing-prototypes]
long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
^
drivers/target/target_core_user.c:2031:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
^
static
2 warnings generated.
vim +/tcmu_ioctl_copy_between_sgl_and_iovec +1987 drivers/target/target_core_user.c
1986
> 1987 long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
1988 struct iovec __user *uiovec,
1989 unsigned long vcnt,
1990 bool is_copy_to_sgl)
1991 {
1992 struct iovec iovstack[UIO_FASTIOV];
1993 struct iovec *iov = iovstack;
1994 struct iov_iter iter;
1995 ssize_t ret;
1996 struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
1997 struct scatterlist *data_sg, *sg;
1998 int i;
1999 unsigned int data_nents;
2000 long copy_ret = 0;
2001
2002 if (se_cmd->se_cmd_flags & SCF_BIDI) {
2003 data_sg = se_cmd->t_bidi_data_sg;
2004 data_nents = se_cmd->t_bidi_data_nents;
2005 } else {
2006 data_sg = se_cmd->t_data_sg;
2007 data_nents = se_cmd->t_data_nents;
2008 }
2009
2010 ret = import_iovec(READ, uiovec, vcnt, ARRAY_SIZE(iovstack), &iov, &iter);
2011 if (ret < 0) {
2012 pr_err("import iovec failed.\n");
2013 return -EFAULT;
2014 }
2015
2016 for_each_sg(data_sg, sg, data_nents, i) {
2017 if (is_copy_to_sgl)
2018 ret = copy_page_from_iter(sg_page(sg), sg->offset, sg->length, &iter);
2019 else
2020 ret = copy_page_to_iter(sg_page(sg), sg->offset, sg->length, &iter);
2021 if (ret < 0) {
2022 pr_err("copy failed.\n");
2023 copy_ret = -EFAULT;
2024 break;
2025 }
2026 }
2027 kfree(iov);
2028 return copy_ret;
2029 }
2030
> 2031 long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
2032 {
2033 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
2034 struct tcmu_data_xfer __user *uxfer = (struct tcmu_data_xfer __user *)arg;
2035 struct tcmu_data_xfer xfer;
2036 struct tcmu_cmd *tcmu_cmd;
2037
2038 if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags))
2039 return -EINVAL;
2040
2041 if (copy_from_user(&xfer, uxfer, sizeof(xfer)))
2042 return -EFAULT;
2043
2044 tcmu_cmd = xa_load(&udev->commands, xfer.cmd_id);
2045 if (!tcmu_cmd) {
2046 set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
2047 return -EFAULT;
2048 }
2049
2050 if (test_bit(TCMU_CMD_BIT_EXPIRED, &tcmu_cmd->flags))
2051 return -EFAULT;
2052
2053 switch (cmd) {
2054 case TCMU_IOCTL_CMD_COPY_TO_SGL:
2055 return tcmu_ioctl_copy_between_sgl_and_iovec(tcmu_cmd, xfer.iovec,
2056 xfer.iov_cnt, true);
2057 case TCMU_IOCTL_CMD_COPY_FROM_SGL:
2058 return tcmu_ioctl_copy_between_sgl_and_iovec(tcmu_cmd, xfer.iovec,
2059 xfer.iov_cnt, false);
2060 default:
2061 return -EINVAL;
2062 }
2063 }
2064
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
drivers/target/target_core_user.c:1987:6: warning: symbol 'tcmu_ioctl_copy_between_sgl_and_iovec' was not declared. Should it be static?
drivers/target/target_core_user.c:2031:6: warning: symbol 'tcmu_ioctl' was not declared. Should it be static?
Reported-by: kernel test robot <[email protected]>
Signed-off-by: kernel test robot <[email protected]>
---
drivers/target/target_core_user.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index afea088f24862b..ea1af59e03deff 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -1984,7 +1984,7 @@ static int tcmu_release(struct uio_info *info, struct inode *inode)
return 0;
}
-long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
+static long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
struct iovec __user *uiovec,
unsigned long vcnt,
bool is_copy_to_sgl)
@@ -2028,7 +2028,7 @@ long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
return copy_ret;
}
-long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
+static long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
{
struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
struct tcmu_data_xfer __user *uxfer = (struct tcmu_data_xfer __user *)arg;
On Thu, Feb 17, 2022 at 10:29:22AM +0800, Guixin Liu wrote:
> --- a/include/uapi/linux/target_core_user.h
> +++ b/include/uapi/linux/target_core_user.h
> @@ -185,4 +185,13 @@ enum tcmu_genl_attr {
> };
> #define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
>
> +struct tcmu_data_xfer {
> + unsigned short cmd_id;
> + unsigned long iov_cnt;
> + struct iovec __user *iovec;
> +};
That is no way to define a structure that crosses the user/kernel
boundry, it just will not work at all, even if we wanted it to :(
sorry,
greg k-h
Liu,
generally I like ideas to speed up tcmu.
OTOH, since Andy Grover implemented tcmu based on uio device, we are
restricted to what uio offers. With today's knowledge I think we would
not use the uio device in tcmu again, but switching away from uio now
would break existing userspace SW.
Before we start thinking how the same performance gain could be reached
without a change in uio device, please let me know why you use file
backend on top of tcmu instead of target_core_file kernel module?
Wouldn't target_core_file be even faster for your purpose?
Bodo
On 17.02.22 03:29, Guixin Liu wrote:
> Currently the data needs to be copied twice between sg, tcmu data area and
> userspace buffer if backstore holds its own userspace buffer, then we can
> use uio ioctl to copy data between sg and userspace buffer directly to
> bypass data area to improve performance.
>
> Use tcm_loop and tcmu(backstore is file) to evaluate performance,
> fio job: fio -filename=/dev/sdb -direct=1 -size=2G -name=1 -thread
> -runtime=60 -time_based -rw=randread -numjobs=16 -iodepth=16 -bs=128k
>
> Without this patch:
> READ: bw=3539MiB/s (3711MB/s), 207MiB/s-233MiB/s (217MB/s-244MB/s),
> io=104GiB (111GB), run=30001-30002msec
>
> With this patch:
> READ: bw=4420MiB/s (4634MB/s), 274MiB/s-278MiB/s (287MB/s-291MB/s),
> io=259GiB (278GB), run=60001-60002msec
>
> Reviewed-by: Xiaoguang Wang <[email protected]>
> Signed-off-by: Guixin Liu <[email protected]>
> ---
> drivers/target/target_core_user.c | 171 +++++++++++++++++++++++++++++-----
> include/uapi/linux/target_core_user.h | 9 ++
> 2 files changed, 157 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
> index 7b2a89a..afea088 100644
> --- a/drivers/target/target_core_user.c
> +++ b/drivers/target/target_core_user.c
> @@ -122,6 +122,7 @@ struct tcmu_dev {
> #define TCMU_DEV_BIT_BLOCKED 2
> #define TCMU_DEV_BIT_TMR_NOTIFY 3
> #define TCMU_DEV_BIT_PLUGGED 4
> +#define TCMU_DEV_BIT_BYPASS_DATA_AREA 5
> unsigned long flags;
>
> struct uio_info uio_info;
> @@ -642,12 +643,17 @@ static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
> tcmu_cmd->se_cmd = se_cmd;
> tcmu_cmd->tcmu_dev = udev;
>
> - tcmu_cmd_set_block_cnts(tcmu_cmd);
> - tcmu_cmd->dbi = kcalloc(tcmu_cmd->dbi_cnt, sizeof(uint32_t),
> - GFP_NOIO);
> - if (!tcmu_cmd->dbi) {
> - kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
> - return NULL;
> + if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags)) {
> + tcmu_cmd_set_block_cnts(tcmu_cmd);
> + tcmu_cmd->dbi = kcalloc(tcmu_cmd->dbi_cnt, sizeof(uint32_t),
> + GFP_NOIO);
> + if (!tcmu_cmd->dbi) {
> + kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
> + return NULL;
> + }
> + } else {
> + tcmu_cmd->dbi_cnt = 0;
> + tcmu_cmd->dbi = NULL;
> }
>
> return tcmu_cmd;
> @@ -1093,16 +1099,18 @@ static int queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, sense_reason_t *scsi_err)
> tcmu_cmd_reset_dbi_cur(tcmu_cmd);
> iov = &entry->req.iov[0];
>
> - if (se_cmd->data_direction == DMA_TO_DEVICE ||
> - se_cmd->se_cmd_flags & SCF_BIDI)
> - scatter_data_area(udev, tcmu_cmd, &iov);
> - else
> - tcmu_setup_iovs(udev, tcmu_cmd, &iov, se_cmd->data_length);
> -
> + if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags)) {
> + if (se_cmd->data_direction == DMA_TO_DEVICE ||
> + se_cmd->se_cmd_flags & SCF_BIDI)
> + scatter_data_area(udev, tcmu_cmd, &iov);
> + else
> + tcmu_setup_iovs(udev, tcmu_cmd, &iov, se_cmd->data_length);
> + }
> entry->req.iov_cnt = iov_cnt - iov_bidi_cnt;
>
> /* Handle BIDI commands */
> - if (se_cmd->se_cmd_flags & SCF_BIDI) {
> + if ((se_cmd->se_cmd_flags & SCF_BIDI)
> + && !test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags)) {
> iov++;
> tcmu_setup_iovs(udev, tcmu_cmd, &iov, tcmu_cmd->data_len_bidi);
> entry->req.iov_bidi_cnt = iov_bidi_cnt;
> @@ -1366,16 +1374,19 @@ static bool tcmu_handle_completion(struct tcmu_cmd *cmd,
> else
> se_cmd->se_cmd_flags |= SCF_TREAT_READ_AS_NORMAL;
> }
> - if (se_cmd->se_cmd_flags & SCF_BIDI) {
> - /* Get Data-In buffer before clean up */
> - gather_data_area(udev, cmd, true, read_len);
> - } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
> - gather_data_area(udev, cmd, false, read_len);
> - } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
> - /* TODO: */
> - } else if (se_cmd->data_direction != DMA_NONE) {
> - pr_warn("TCMU: data direction was %d!\n",
> - se_cmd->data_direction);
> +
> + if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags)) {
> + if (se_cmd->se_cmd_flags & SCF_BIDI) {
> + /* Get Data-In buffer before clean up */
> + gather_data_area(udev, cmd, true, read_len);
> + } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
> + gather_data_area(udev, cmd, false, read_len);
> + } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
> + /* TODO: */
> + } else if (se_cmd->data_direction != DMA_NONE) {
> + pr_warn("TCMU: data direction was %d!\n",
> + se_cmd->data_direction);
> + }
> }
>
> done:
> @@ -1973,6 +1984,84 @@ static int tcmu_release(struct uio_info *info, struct inode *inode)
> return 0;
> }
>
> +long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
> + struct iovec __user *uiovec,
> + unsigned long vcnt,
> + bool is_copy_to_sgl)
> +{
> + struct iovec iovstack[UIO_FASTIOV];
> + struct iovec *iov = iovstack;
> + struct iov_iter iter;
> + ssize_t ret;
> + struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
> + struct scatterlist *data_sg, *sg;
> + int i;
> + unsigned int data_nents;
> + long copy_ret = 0;
> +
> + if (se_cmd->se_cmd_flags & SCF_BIDI) {
> + data_sg = se_cmd->t_bidi_data_sg;
> + data_nents = se_cmd->t_bidi_data_nents;
> + } else {
> + data_sg = se_cmd->t_data_sg;
> + data_nents = se_cmd->t_data_nents;
> + }
> +
> + ret = import_iovec(READ, uiovec, vcnt, ARRAY_SIZE(iovstack), &iov, &iter);
> + if (ret < 0) {
> + pr_err("import iovec failed.\n");
> + return -EFAULT;
> + }
> +
> + for_each_sg(data_sg, sg, data_nents, i) {
> + if (is_copy_to_sgl)
> + ret = copy_page_from_iter(sg_page(sg), sg->offset, sg->length, &iter);
> + else
> + ret = copy_page_to_iter(sg_page(sg), sg->offset, sg->length, &iter);
> + if (ret < 0) {
> + pr_err("copy failed.\n");
> + copy_ret = -EFAULT;
> + break;
> + }
> + }
> + kfree(iov);
> + return copy_ret;
> +}
> +
> +long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
> +{
> + struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
> + struct tcmu_data_xfer __user *uxfer = (struct tcmu_data_xfer __user *)arg;
> + struct tcmu_data_xfer xfer;
> + struct tcmu_cmd *tcmu_cmd;
> +
> + if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags))
> + return -EINVAL;
> +
> + if (copy_from_user(&xfer, uxfer, sizeof(xfer)))
> + return -EFAULT;
> +
> + tcmu_cmd = xa_load(&udev->commands, xfer.cmd_id);
> + if (!tcmu_cmd) {
> + set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
> + return -EFAULT;
> + }
> +
> + if (test_bit(TCMU_CMD_BIT_EXPIRED, &tcmu_cmd->flags))
> + return -EFAULT;
> +
> + switch (cmd) {
> + case TCMU_IOCTL_CMD_COPY_TO_SGL:
> + return tcmu_ioctl_copy_between_sgl_and_iovec(tcmu_cmd, xfer.iovec,
> + xfer.iov_cnt, true);
> + case TCMU_IOCTL_CMD_COPY_FROM_SGL:
> + return tcmu_ioctl_copy_between_sgl_and_iovec(tcmu_cmd, xfer.iovec,
> + xfer.iov_cnt, false);
> + default:
> + return -EINVAL;
> + }
> +}
> +
> static int tcmu_init_genl_cmd_reply(struct tcmu_dev *udev, int cmd)
> {
> struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
> @@ -2230,6 +2319,7 @@ static int tcmu_configure_device(struct se_device *dev)
> info->mmap = tcmu_mmap;
> info->open = tcmu_open;
> info->release = tcmu_release;
> + info->ioctl = tcmu_ioctl;
>
> ret = uio_register_device(tcmu_root_device, info);
> if (ret)
> @@ -2838,6 +2928,40 @@ static ssize_t tcmu_nl_reply_supported_store(struct config_item *item,
> }
> CONFIGFS_ATTR(tcmu_, nl_reply_supported);
>
> +static ssize_t tcmu_bypass_data_area_show(struct config_item *item, char *page)
> +{
> + struct se_dev_attrib *da = container_of(to_config_group(item),
> + struct se_dev_attrib, da_group);
> + struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
> +
> + if (test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags))
> + return snprintf(page, PAGE_SIZE, "%s\n", "true");
> + else
> + return snprintf(page, PAGE_SIZE, "%s\n", "false");
> +}
> +
> +static ssize_t tcmu_bypass_data_area_store(struct config_item *item, const char *page,
> + size_t count)
> +{
> + struct se_dev_attrib *da = container_of(to_config_group(item),
> + struct se_dev_attrib, da_group);
> + struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
> + bool bypass_data_area;
> + int ret;
> +
> + ret = strtobool(page, &bypass_data_area);
> + if (ret < 0)
> + return ret;
> +
> + if (bypass_data_area)
> + set_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags);
> + else
> + clear_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags);
> +
> + return count;
> +}
> +CONFIGFS_ATTR(tcmu_, bypass_data_area);
> +
> static ssize_t tcmu_emulate_write_cache_show(struct config_item *item,
> char *page)
> {
> @@ -3069,6 +3193,7 @@ static ssize_t tcmu_free_kept_buf_store(struct config_item *item, const char *pa
> &tcmu_attr_emulate_write_cache,
> &tcmu_attr_tmr_notification,
> &tcmu_attr_nl_reply_supported,
> + &tcmu_attr_bypass_data_area,
> NULL,
> };
>
> diff --git a/include/uapi/linux/target_core_user.h b/include/uapi/linux/target_core_user.h
> index 27ace51..c02a45e 100644
> --- a/include/uapi/linux/target_core_user.h
> +++ b/include/uapi/linux/target_core_user.h
> @@ -185,4 +185,13 @@ enum tcmu_genl_attr {
> };
> #define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
>
> +struct tcmu_data_xfer {
> + unsigned short cmd_id;
> + unsigned long iov_cnt;
> + struct iovec __user *iovec;
> +};
> +
> +#define TCMU_IOCTL_CMD_COPY_TO_SGL _IOW('T', 0xe0, struct tcmu_data_xfer)
> +#define TCMU_IOCTL_CMD_COPY_FROM_SGL _IOW('T', 0xe1, struct tcmu_data_xfer)
> +
> #endif
hi Bodo,
> Liu,
>
> generally I like ideas to speed up tcmu.
>
> OTOH, since Andy Grover implemented tcmu based on uio device, we are
> restricted to what uio offers. With today's knowledge I think we would
> not use the uio device in tcmu again, but switching away from uio now
> would break existing userspace SW.
Yeah, it will have much work if deciding to switch away from uio.
I came up with a hacky or crazy idea :) what about we create a new file
in tcmu_open() by anon_inode_getfile_secure(), and export this fd by
tcmu mail box, we can do ioctl() on this new file, then uio framework
won't be touched...
static int tcmu_open(struct uio_info *info, struct inode *inode)
{
struct tcmu_dev *udev = container_of(info, struct tcmu_dev,
uio_info);
/* O_EXCL not supported for char devs, so fake it? */
if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
return -EBUSY;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
tcmu device can only be opened once before closed.
Regards,
Xiaoguang Wang
>
> Before we start thinking how the same performance gain could be reached
> without a change in uio device, please let me know why you use file
> backend on top of tcmu instead of target_core_file kernel module?
> Wouldn't target_core_file be even faster for your purpose?
>
> Bodo
>
>
>
> On 17.02.22 03:29, Guixin Liu wrote:
>> Currently the data needs to be copied twice between sg, tcmu data
>> area and
>> userspace buffer if backstore holds its own userspace buffer, then we
>> can
>> use uio ioctl to copy data between sg and userspace buffer directly to
>> bypass data area to improve performance.
>>
>> Use tcm_loop and tcmu(backstore is file) to evaluate performance,
>> fio job: fio -filename=/dev/sdb -direct=1 -size=2G -name=1 -thread
>> -runtime=60 -time_based -rw=randread -numjobs=16 -iodepth=16 -bs=128k
>>
>> Without this patch:
>> READ: bw=3539MiB/s (3711MB/s), 207MiB/s-233MiB/s (217MB/s-244MB/s),
>> io=104GiB (111GB), run=30001-30002msec
>>
>> With this patch:
>> READ: bw=4420MiB/s (4634MB/s), 274MiB/s-278MiB/s (287MB/s-291MB/s),
>> io=259GiB (278GB), run=60001-60002msec
>>
>> Reviewed-by: Xiaoguang Wang <[email protected]>
>> Signed-off-by: Guixin Liu <[email protected]>
>> ---
>> drivers/target/target_core_user.c | 171
>> +++++++++++++++++++++++++++++-----
>> include/uapi/linux/target_core_user.h | 9 ++
>> 2 files changed, 157 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/target/target_core_user.c
>> b/drivers/target/target_core_user.c
>> index 7b2a89a..afea088 100644
>> --- a/drivers/target/target_core_user.c
>> +++ b/drivers/target/target_core_user.c
>> @@ -122,6 +122,7 @@ struct tcmu_dev {
>> #define TCMU_DEV_BIT_BLOCKED 2
>> #define TCMU_DEV_BIT_TMR_NOTIFY 3
>> #define TCMU_DEV_BIT_PLUGGED 4
>> +#define TCMU_DEV_BIT_BYPASS_DATA_AREA 5
>> unsigned long flags;
>> struct uio_info uio_info;
>> @@ -642,12 +643,17 @@ static struct tcmu_cmd *tcmu_alloc_cmd(struct
>> se_cmd *se_cmd)
>> tcmu_cmd->se_cmd = se_cmd;
>> tcmu_cmd->tcmu_dev = udev;
>> - tcmu_cmd_set_block_cnts(tcmu_cmd);
>> - tcmu_cmd->dbi = kcalloc(tcmu_cmd->dbi_cnt, sizeof(uint32_t),
>> - GFP_NOIO);
>> - if (!tcmu_cmd->dbi) {
>> - kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
>> - return NULL;
>> + if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags)) {
>> + tcmu_cmd_set_block_cnts(tcmu_cmd);
>> + tcmu_cmd->dbi = kcalloc(tcmu_cmd->dbi_cnt, sizeof(uint32_t),
>> + GFP_NOIO);
>> + if (!tcmu_cmd->dbi) {
>> + kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
>> + return NULL;
>> + }
>> + } else {
>> + tcmu_cmd->dbi_cnt = 0;
>> + tcmu_cmd->dbi = NULL;
>> }
>> return tcmu_cmd;
>> @@ -1093,16 +1099,18 @@ static int queue_cmd_ring(struct tcmu_cmd
>> *tcmu_cmd, sense_reason_t *scsi_err)
>> tcmu_cmd_reset_dbi_cur(tcmu_cmd);
>> iov = &entry->req.iov[0];
>> - if (se_cmd->data_direction == DMA_TO_DEVICE ||
>> - se_cmd->se_cmd_flags & SCF_BIDI)
>> - scatter_data_area(udev, tcmu_cmd, &iov);
>> - else
>> - tcmu_setup_iovs(udev, tcmu_cmd, &iov, se_cmd->data_length);
>> -
>> + if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags)) {
>> + if (se_cmd->data_direction == DMA_TO_DEVICE ||
>> + se_cmd->se_cmd_flags & SCF_BIDI)
>> + scatter_data_area(udev, tcmu_cmd, &iov);
>> + else
>> + tcmu_setup_iovs(udev, tcmu_cmd, &iov, se_cmd->data_length);
>> + }
>> entry->req.iov_cnt = iov_cnt - iov_bidi_cnt;
>> /* Handle BIDI commands */
>> - if (se_cmd->se_cmd_flags & SCF_BIDI) {
>> + if ((se_cmd->se_cmd_flags & SCF_BIDI)
>> + && !test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags)) {
>> iov++;
>> tcmu_setup_iovs(udev, tcmu_cmd, &iov,
>> tcmu_cmd->data_len_bidi);
>> entry->req.iov_bidi_cnt = iov_bidi_cnt;
>> @@ -1366,16 +1374,19 @@ static bool tcmu_handle_completion(struct
>> tcmu_cmd *cmd,
>> else
>> se_cmd->se_cmd_flags |= SCF_TREAT_READ_AS_NORMAL;
>> }
>> - if (se_cmd->se_cmd_flags & SCF_BIDI) {
>> - /* Get Data-In buffer before clean up */
>> - gather_data_area(udev, cmd, true, read_len);
>> - } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
>> - gather_data_area(udev, cmd, false, read_len);
>> - } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
>> - /* TODO: */
>> - } else if (se_cmd->data_direction != DMA_NONE) {
>> - pr_warn("TCMU: data direction was %d!\n",
>> - se_cmd->data_direction);
>> +
>> + if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags)) {
>> + if (se_cmd->se_cmd_flags & SCF_BIDI) {
>> + /* Get Data-In buffer before clean up */
>> + gather_data_area(udev, cmd, true, read_len);
>> + } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
>> + gather_data_area(udev, cmd, false, read_len);
>> + } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
>> + /* TODO: */
>> + } else if (se_cmd->data_direction != DMA_NONE) {
>> + pr_warn("TCMU: data direction was %d!\n",
>> + se_cmd->data_direction);
>> + }
>> }
>> done:
>> @@ -1973,6 +1984,84 @@ static int tcmu_release(struct uio_info *info,
>> struct inode *inode)
>> return 0;
>> }
>> +long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
>> + struct iovec __user *uiovec,
>> + unsigned long vcnt,
>> + bool is_copy_to_sgl)
>> +{
>> + struct iovec iovstack[UIO_FASTIOV];
>> + struct iovec *iov = iovstack;
>> + struct iov_iter iter;
>> + ssize_t ret;
>> + struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
>> + struct scatterlist *data_sg, *sg;
>> + int i;
>> + unsigned int data_nents;
>> + long copy_ret = 0;
>> +
>> + if (se_cmd->se_cmd_flags & SCF_BIDI) {
>> + data_sg = se_cmd->t_bidi_data_sg;
>> + data_nents = se_cmd->t_bidi_data_nents;
>> + } else {
>> + data_sg = se_cmd->t_data_sg;
>> + data_nents = se_cmd->t_data_nents;
>> + }
>> +
>> + ret = import_iovec(READ, uiovec, vcnt, ARRAY_SIZE(iovstack),
>> &iov, &iter);
>> + if (ret < 0) {
>> + pr_err("import iovec failed.\n");
>> + return -EFAULT;
>> + }
>> +
>> + for_each_sg(data_sg, sg, data_nents, i) {
>> + if (is_copy_to_sgl)
>> + ret = copy_page_from_iter(sg_page(sg), sg->offset,
>> sg->length, &iter);
>> + else
>> + ret = copy_page_to_iter(sg_page(sg), sg->offset,
>> sg->length, &iter);
>> + if (ret < 0) {
>> + pr_err("copy failed.\n");
>> + copy_ret = -EFAULT;
>> + break;
>> + }
>> + }
>> + kfree(iov);
>> + return copy_ret;
>> +}
>> +
>> +long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned
>> long arg)
>> +{
>> + struct tcmu_dev *udev = container_of(info, struct tcmu_dev,
>> uio_info);
>> + struct tcmu_data_xfer __user *uxfer = (struct tcmu_data_xfer
>> __user *)arg;
>> + struct tcmu_data_xfer xfer;
>> + struct tcmu_cmd *tcmu_cmd;
>> +
>> + if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags))
>> + return -EINVAL;
>> +
>> + if (copy_from_user(&xfer, uxfer, sizeof(xfer)))
>> + return -EFAULT;
>> +
>> + tcmu_cmd = xa_load(&udev->commands, xfer.cmd_id);
>> + if (!tcmu_cmd) {
>> + set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
>> + return -EFAULT;
>> + }
>> +
>> + if (test_bit(TCMU_CMD_BIT_EXPIRED, &tcmu_cmd->flags))
>> + return -EFAULT;
>> +
>> + switch (cmd) {
>> + case TCMU_IOCTL_CMD_COPY_TO_SGL:
>> + return tcmu_ioctl_copy_between_sgl_and_iovec(tcmu_cmd,
>> xfer.iovec,
>> + xfer.iov_cnt, true);
>> + case TCMU_IOCTL_CMD_COPY_FROM_SGL:
>> + return tcmu_ioctl_copy_between_sgl_and_iovec(tcmu_cmd,
>> xfer.iovec,
>> + xfer.iov_cnt, false);
>> + default:
>> + return -EINVAL;
>> + }
>> +}
>> +
>> static int tcmu_init_genl_cmd_reply(struct tcmu_dev *udev, int cmd)
>> {
>> struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
>> @@ -2230,6 +2319,7 @@ static int tcmu_configure_device(struct
>> se_device *dev)
>> info->mmap = tcmu_mmap;
>> info->open = tcmu_open;
>> info->release = tcmu_release;
>> + info->ioctl = tcmu_ioctl;
>> ret = uio_register_device(tcmu_root_device, info);
>> if (ret)
>> @@ -2838,6 +2928,40 @@ static ssize_t
>> tcmu_nl_reply_supported_store(struct config_item *item,
>> }
>> CONFIGFS_ATTR(tcmu_, nl_reply_supported);
>> +static ssize_t tcmu_bypass_data_area_show(struct config_item
>> *item, char *page)
>> +{
>> + struct se_dev_attrib *da = container_of(to_config_group(item),
>> + struct se_dev_attrib, da_group);
>> + struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
>> +
>> + if (test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags))
>> + return snprintf(page, PAGE_SIZE, "%s\n", "true");
>> + else
>> + return snprintf(page, PAGE_SIZE, "%s\n", "false");
>> +}
>> +
>> +static ssize_t tcmu_bypass_data_area_store(struct config_item *item,
>> const char *page,
>> + size_t count)
>> +{
>> + struct se_dev_attrib *da = container_of(to_config_group(item),
>> + struct se_dev_attrib, da_group);
>> + struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
>> + bool bypass_data_area;
>> + int ret;
>> +
>> + ret = strtobool(page, &bypass_data_area);
>> + if (ret < 0)
>> + return ret;
>> +
>> + if (bypass_data_area)
>> + set_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags);
>> + else
>> + clear_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags);
>> +
>> + return count;
>> +}
>> +CONFIGFS_ATTR(tcmu_, bypass_data_area);
>> +
>> static ssize_t tcmu_emulate_write_cache_show(struct config_item *item,
>> char *page)
>> {
>> @@ -3069,6 +3193,7 @@ static ssize_t tcmu_free_kept_buf_store(struct
>> config_item *item, const char *pa
>> &tcmu_attr_emulate_write_cache,
>> &tcmu_attr_tmr_notification,
>> &tcmu_attr_nl_reply_supported,
>> + &tcmu_attr_bypass_data_area,
>> NULL,
>> };
>> diff --git a/include/uapi/linux/target_core_user.h
>> b/include/uapi/linux/target_core_user.h
>> index 27ace51..c02a45e 100644
>> --- a/include/uapi/linux/target_core_user.h
>> +++ b/include/uapi/linux/target_core_user.h
>> @@ -185,4 +185,13 @@ enum tcmu_genl_attr {
>> };
>> #define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
>> +struct tcmu_data_xfer {
>> + unsigned short cmd_id;
>> + unsigned long iov_cnt;
>> + struct iovec __user *iovec;
>> +};
>> +
>> +#define TCMU_IOCTL_CMD_COPY_TO_SGL _IOW('T', 0xe0, struct
>> tcmu_data_xfer)
>> +#define TCMU_IOCTL_CMD_COPY_FROM_SGL _IOW('T', 0xe1, struct
>> tcmu_data_xfer)
>> +
>> #endif
On Mon, Feb 28, 2022 at 04:52:52PM +0800, Xiaoguang Wang wrote:
>
> hi Bodo,
>
> > Liu,
> >
> > generally I like ideas to speed up tcmu.
> >
> > OTOH, since Andy Grover implemented tcmu based on uio device, we are
> > restricted to what uio offers. With today's knowledge I think we would
> > not use the uio device in tcmu again, but switching away from uio now
> > would break existing userspace SW.
> Yeah, it will have much work if deciding to switch away from uio.
> I came up with a hacky or crazy idea :) what about we create a new file
> in tcmu_open() by anon_inode_getfile_secure(), and export this fd by
> tcmu mail box, we can do ioctl() on this new file, then uio framework
> won't be touched...
No new ioctls please. That is creating a new user/kernel api that you
must support for the next 20+ years. Please do not do that.
thanks,
greg k-h