This series contains few clean up, minor bug fixes and
Convert get_user_pages() to pin_user_pages().
I'm compile tested this, but unable to run-time test,
so any testing help is much appriciated.
v2:
Address Dan's review comments to return -ERRNO for partially
mapped pages and changed the other patches in series accordingly.
Minor update in change logs.
Cc: John Hubbard <[email protected]>
Cc: Bharath Vedartham <[email protected]>
Cc: Dan Carpenter <[email protected]>
Souptick Joarder (4):
staging: kpc2000: kpc_dma: Unpin partial pinned pages
staging: kpc2000: kpc_dma: Convert set_page_dirty() -->
set_page_dirty_lock()
staging: kpc2000: kpc_dma: Convert get_user_pages() -->
pin_user_pages()
staging: kpc2000: kpc_dma: Remove additional goto statements
drivers/staging/kpc2000/kpc_dma/fileops.c | 38 ++++++++++++++++---------------
1 file changed, 20 insertions(+), 18 deletions(-)
--
1.9.1
There is a bug, when get_user_pages() failed but partially pinned
pages are not unpinned and positive numbers are returned instead of
-ERRNO. Fixed it.
Also, int is more appropriate type for rv. Changed it.
Signed-off-by: Souptick Joarder <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Dan Carpenter <[email protected]>
Cc: Bharath Vedartham <[email protected]>
---
drivers/staging/kpc2000/kpc_dma/fileops.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c
index 8975346..becdb41 100644
--- a/drivers/staging/kpc2000/kpc_dma/fileops.c
+++ b/drivers/staging/kpc2000/kpc_dma/fileops.c
@@ -35,7 +35,7 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
unsigned long iov_base, size_t iov_len)
{
unsigned int i = 0;
- long rv = 0;
+ int rv = 0;
struct kpc_dma_device *ldev;
struct aio_cb_data *acd;
DECLARE_COMPLETION_ONSTACK(done);
@@ -79,14 +79,14 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
rv = get_user_pages(iov_base, acd->page_count, FOLL_TOUCH | FOLL_WRITE | FOLL_GET, acd->user_pages, NULL);
mmap_read_unlock(current->mm); /* release the semaphore */
if (rv != acd->page_count) {
- dev_err(&priv->ldev->pldev->dev, "Couldn't get_user_pages (%ld)\n", rv);
+ dev_err(&priv->ldev->pldev->dev, "Couldn't get_user_pages (%d)\n", rv);
goto err_get_user_pages;
}
// Allocate and setup the sg_table (scatterlist entries)
rv = sg_alloc_table_from_pages(&acd->sgt, acd->user_pages, acd->page_count, iov_base & (PAGE_SIZE - 1), iov_len, GFP_KERNEL);
if (rv) {
- dev_err(&priv->ldev->pldev->dev, "Couldn't alloc sg_table (%ld)\n", rv);
+ dev_err(&priv->ldev->pldev->dev, "Couldn't alloc sg_table (%d)\n", rv);
goto err_alloc_sg_table;
}
@@ -193,10 +193,15 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
put_page(acd->user_pages[i]);
err_get_user_pages:
+ if (rv > 0) {
+ for (i = 0; i < rv; i++)
+ put_pages(acd->user_pages[i]);
+ rv = -EFAULT;
+ }
kfree(acd->user_pages);
err_alloc_userpages:
kfree(acd);
- dev_dbg(&priv->ldev->pldev->dev, "%s returning with error %ld\n", __func__, rv);
+ dev_dbg(&priv->ldev->pldev->dev, "%s returning with error %d\n", __func__, rv);
return rv;
}
--
1.9.1
In 2019, we introduced pin_user_pages*() and now we are converting
get_user_pages*() to the new API as appropriate. [1] & [2] could
be referred for more information. This is case 2 as per document [1].
[1] Documentation/core-api/pin_user_pages.rst
[2] "Explicit pinning of user-space pages":
https://lwn.net/Articles/807108/
Signed-off-by: Souptick Joarder <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Bharath Vedartham <[email protected]>
Cc: Dan Carpenter <[email protected]>
---
drivers/staging/kpc2000/kpc_dma/fileops.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c
index 08d90a6..8cd20ad 100644
--- a/drivers/staging/kpc2000/kpc_dma/fileops.c
+++ b/drivers/staging/kpc2000/kpc_dma/fileops.c
@@ -76,10 +76,10 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
// Lock the user buffer pages in memory, and hold on to the page pointers (for the sglist)
mmap_read_lock(current->mm); /* get memory map semaphore */
- rv = get_user_pages(iov_base, acd->page_count, FOLL_TOUCH | FOLL_WRITE | FOLL_GET, acd->user_pages, NULL);
+ rv = pin_user_pages(iov_base, acd->page_count, FOLL_TOUCH | FOLL_WRITE, acd->user_pages, NULL);
mmap_read_unlock(current->mm); /* release the semaphore */
if (rv != acd->page_count) {
- dev_err(&priv->ldev->pldev->dev, "Couldn't get_user_pages (%d)\n", rv);
+ dev_err(&priv->ldev->pldev->dev, "Couldn't pin_user_pages (%d)\n", rv);
goto err_get_user_pages;
}
@@ -189,13 +189,11 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
sg_free_table(&acd->sgt);
err_dma_map_sg:
err_alloc_sg_table:
- for (i = 0 ; i < acd->page_count ; i++)
- put_page(acd->user_pages[i]);
+ unpin_user_pages(acd->user_pages, acd->page_count);
err_get_user_pages:
if (rv > 0) {
- for (i = 0; i < rv; i++)
- put_pages(acd->user_pages[i]);
+ unpin_user_pages(acd->user_pages, rv);
rv = -EFAULT;
}
kfree(acd->user_pages);
@@ -222,8 +220,7 @@ void transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags)
set_page_dirty_lock(acd->user_pages[i]);
}
- for (i = 0 ; i < acd->page_count ; i++)
- put_page(acd->user_pages[i]);
+ unpin_user_pages(acd->user_pages, acd->page_count);
sg_free_table(&acd->sgt);
--
1.9.1
As 3 goto level referring to same common code, those can be
accomodated with a single goto level and renameing it to
unpin_pages. Set the -ERRNO when returning partial mapped
pages in more appropriate place.
Signed-off-by: Souptick Joarder <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Bharath Vedartham <[email protected]>
Cc: Dan Carpenter <[email protected]>
---
drivers/staging/kpc2000/kpc_dma/fileops.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c
index 8cd20ad..d21a4fd 100644
--- a/drivers/staging/kpc2000/kpc_dma/fileops.c
+++ b/drivers/staging/kpc2000/kpc_dma/fileops.c
@@ -35,7 +35,7 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
unsigned long iov_base, size_t iov_len)
{
unsigned int i = 0;
- int rv = 0;
+ int rv = 0, nr_pages = 0;
struct kpc_dma_device *ldev;
struct aio_cb_data *acd;
DECLARE_COMPLETION_ONSTACK(done);
@@ -79,22 +79,27 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
rv = pin_user_pages(iov_base, acd->page_count, FOLL_TOUCH | FOLL_WRITE, acd->user_pages, NULL);
mmap_read_unlock(current->mm); /* release the semaphore */
if (rv != acd->page_count) {
+ nr_pages = rv;
+ if (rv > 0)
+ rv = -EFAULT;
+
dev_err(&priv->ldev->pldev->dev, "Couldn't pin_user_pages (%d)\n", rv);
- goto err_get_user_pages;
+ goto unpin_pages;
}
+ nr_pages = acd->page_count;
// Allocate and setup the sg_table (scatterlist entries)
rv = sg_alloc_table_from_pages(&acd->sgt, acd->user_pages, acd->page_count, iov_base & (PAGE_SIZE - 1), iov_len, GFP_KERNEL);
if (rv) {
dev_err(&priv->ldev->pldev->dev, "Couldn't alloc sg_table (%d)\n", rv);
- goto err_alloc_sg_table;
+ goto unpin_pages;
}
// Setup the DMA mapping for all the sg entries
acd->mapped_entry_count = dma_map_sg(&ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, ldev->dir);
if (acd->mapped_entry_count <= 0) {
dev_err(&priv->ldev->pldev->dev, "Couldn't dma_map_sg (%d)\n", acd->mapped_entry_count);
- goto err_dma_map_sg;
+ goto unpin_pages;
}
// Calculate how many descriptors are actually needed for this transfer.
@@ -187,15 +192,10 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
unlock_engine(ldev);
dma_unmap_sg(&ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, ldev->dir);
sg_free_table(&acd->sgt);
- err_dma_map_sg:
- err_alloc_sg_table:
- unpin_user_pages(acd->user_pages, acd->page_count);
- err_get_user_pages:
- if (rv > 0) {
- unpin_user_pages(acd->user_pages, rv);
- rv = -EFAULT;
- }
+ unpin_pages:
+ if (nr_pages > 0)
+ unpin_user_pages(acd->user_pages, nr_pages);
kfree(acd->user_pages);
err_alloc_userpages:
kfree(acd);
--
1.9.1
First, convert set_page_dirty() to set_page_dirty_lock()
Second, there is an interval in there after set_page_dirty() and
before put_page(), in which the device could be running and setting
pages dirty. Moving set_page_dirty_lock() after dma_unmap_sg().
Signed-off-by: Souptick Joarder <[email protected]>
Suggested-by: John Hubbard <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Bharath Vedartham <[email protected]>
Cc: Dan Carpenter <[email protected]>
---
drivers/staging/kpc2000/kpc_dma/fileops.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c
index becdb41..08d90a6 100644
--- a/drivers/staging/kpc2000/kpc_dma/fileops.c
+++ b/drivers/staging/kpc2000/kpc_dma/fileops.c
@@ -215,13 +215,13 @@ void transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags)
BUG_ON(!acd->ldev);
BUG_ON(!acd->ldev->pldev);
+ dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir);
+
for (i = 0 ; i < acd->page_count ; i++) {
if (!PageReserved(acd->user_pages[i]))
- set_page_dirty(acd->user_pages[i]);
+ set_page_dirty_lock(acd->user_pages[i]);
}
- dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir);
-
for (i = 0 ; i < acd->page_count ; i++)
put_page(acd->user_pages[i]);
--
1.9.1
On Tue, Jun 30, 2020 at 01:22:19PM +0530, Souptick Joarder wrote:
> As 3 goto level referring to same common code, those can be
> accomodated with a single goto level and renameing it to
> unpin_pages. Set the -ERRNO when returning partial mapped
> pages in more appropriate place.
>
> Signed-off-by: Souptick Joarder <[email protected]>
> Cc: John Hubbard <[email protected]>
> Cc: Bharath Vedartham <[email protected]>
> Cc: Dan Carpenter <[email protected]>
> ---
> drivers/staging/kpc2000/kpc_dma/fileops.c | 24 ++++++++++++------------
> 1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c
> index 8cd20ad..d21a4fd 100644
> --- a/drivers/staging/kpc2000/kpc_dma/fileops.c
> +++ b/drivers/staging/kpc2000/kpc_dma/fileops.c
> @@ -35,7 +35,7 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
> unsigned long iov_base, size_t iov_len)
> {
> unsigned int i = 0;
> - int rv = 0;
> + int rv = 0, nr_pages = 0;
> struct kpc_dma_device *ldev;
> struct aio_cb_data *acd;
> DECLARE_COMPLETION_ONSTACK(done);
> @@ -79,22 +79,27 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
> rv = pin_user_pages(iov_base, acd->page_count, FOLL_TOUCH | FOLL_WRITE, acd->user_pages, NULL);
> mmap_read_unlock(current->mm); /* release the semaphore */
> if (rv != acd->page_count) {
> + nr_pages = rv;
> + if (rv > 0)
> + rv = -EFAULT;
> +
> dev_err(&priv->ldev->pldev->dev, "Couldn't pin_user_pages (%d)\n", rv);
> - goto err_get_user_pages;
> + goto unpin_pages;
> }
> + nr_pages = acd->page_count;
>
> // Allocate and setup the sg_table (scatterlist entries)
> rv = sg_alloc_table_from_pages(&acd->sgt, acd->user_pages, acd->page_count, iov_base & (PAGE_SIZE - 1), iov_len, GFP_KERNEL);
> if (rv) {
> dev_err(&priv->ldev->pldev->dev, "Couldn't alloc sg_table (%d)\n", rv);
> - goto err_alloc_sg_table;
> + goto unpin_pages;
> }
>
> // Setup the DMA mapping for all the sg entries
> acd->mapped_entry_count = dma_map_sg(&ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, ldev->dir);
> if (acd->mapped_entry_count <= 0) {
> dev_err(&priv->ldev->pldev->dev, "Couldn't dma_map_sg (%d)\n", acd->mapped_entry_count);
> - goto err_dma_map_sg;
> + goto unpin_pages;
This wasn't introduced by your patch but the most recent successful
allocation is sg_alloc_table_from_pages() so this should be goto
free_table:
free_table:
sg_free_table(&acd->sgt);
unpin_pages:
if (nr_pages > 0)
unpin_user_pages(acd->user_pages, nr_pages);
Always just keep track of the most recent allocation and check that the
"goto free_foo" matches what you would expect to release the most
recent thing.
> }
>
> // Calculate how many descriptors are actually needed for this transfer.
> @@ -187,15 +192,10 @@ static int kpc_dma_transfer(struct dev_private_data *priv,
> unlock_engine(ldev);
> dma_unmap_sg(&ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, ldev->dir);
> sg_free_table(&acd->sgt);
^^^^^^^^^^^^^^^^^^^^^^^^
> - err_dma_map_sg:
> - err_alloc_sg_table:
> - unpin_user_pages(acd->user_pages, acd->page_count);
>
> - err_get_user_pages:
> - if (rv > 0) {
> - unpin_user_pages(acd->user_pages, rv);
> - rv = -EFAULT;
> - }
> + unpin_pages:
> + if (nr_pages > 0)
> + unpin_user_pages(acd->user_pages, nr_pages);
> kfree(acd->user_pages);
> err_alloc_userpages:
> kfree(acd);
regards,
dan carpenter