We can simplifly code around cache_downcall unifying memory
allocations using kvmalloc, this have the benefit of getting rid of
cache_slow_downcall (and queue_io_mutex), and also matches userland
allocation size and limits
Signed-off-by: Roberto Bergantinos Corpas <[email protected]>
---
net/sunrpc/cache.c | 41 +++++++++++------------------------------
1 file changed, 11 insertions(+), 30 deletions(-)
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index baef5ee43dbb..1347ecae9c84 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -777,7 +777,6 @@ void cache_clean_deferred(void *owner)
*/
static DEFINE_SPINLOCK(queue_lock);
-static DEFINE_MUTEX(queue_io_mutex);
struct cache_queue {
struct list_head list;
@@ -905,44 +904,26 @@ static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
return ret;
}
-static ssize_t cache_slow_downcall(const char __user *buf,
- size_t count, struct cache_detail *cd)
-{
- static char write_buf[8192]; /* protected by queue_io_mutex */
- ssize_t ret = -EINVAL;
-
- if (count >= sizeof(write_buf))
- goto out;
- mutex_lock(&queue_io_mutex);
- ret = cache_do_downcall(write_buf, buf, count, cd);
- mutex_unlock(&queue_io_mutex);
-out:
- return ret;
-}
-
static ssize_t cache_downcall(struct address_space *mapping,
const char __user *buf,
size_t count, struct cache_detail *cd)
{
- struct page *page;
- char *kaddr;
+ char *write_buf;
ssize_t ret = -ENOMEM;
- if (count >= PAGE_SIZE)
- goto out_slow;
+ if (count >= 32768) { /* 32k is max userland buffer, lets check anyway */
+ ret = -EINVAL;
+ goto out;
+ }
- page = find_or_create_page(mapping, 0, GFP_KERNEL);
- if (!page)
- goto out_slow;
+ write_buf = kvmalloc(count + 1, GFP_KERNEL);
+ if (!write_buf)
+ goto out;
- kaddr = kmap(page);
- ret = cache_do_downcall(kaddr, buf, count, cd);
- kunmap(page);
- unlock_page(page);
- put_page(page);
+ ret = cache_do_downcall(write_buf, buf, count, cd);
+ kvfree(write_buf);
+out:
return ret;
-out_slow:
- return cache_slow_downcall(buf, count, cd);
}
static ssize_t cache_write(struct file *filp, const char __user *buf,
--
2.21.0
Hi Roberto-
I spotted some mechanical problems.
> On Nov 27, 2020, at 11:14 AM, Roberto Bergantinos Corpas <[email protected]> wrote:
>
> We can simplifly code around cache_downcall unifying memory
^simplifly^simplify
> allocations using kvmalloc, this have the benefit of getting rid of
^, this have^. This has
> cache_slow_downcall (and queue_io_mutex), and also matches userland
> allocation size and limits
>
> Signed-off-by: Roberto Bergantinos Corpas <[email protected]>
Assuming Bruce is copacetic with this patch, the change looks
appropriate for the v5.11 merge window. However, this patch
doesn't appear to apply to v5.10-rc5. Might be because
27a1e8a0f79e ("sunrpc: raise kernel RPC channel buffer size")
was already merged?
> ---
> net/sunrpc/cache.c | 41 +++++++++++------------------------------
> 1 file changed, 11 insertions(+), 30 deletions(-)
>
> diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
> index baef5ee43dbb..1347ecae9c84 100644
> --- a/net/sunrpc/cache.c
> +++ b/net/sunrpc/cache.c
> @@ -777,7 +777,6 @@ void cache_clean_deferred(void *owner)
> */
>
> static DEFINE_SPINLOCK(queue_lock);
> -static DEFINE_MUTEX(queue_io_mutex);
>
> struct cache_queue {
> struct list_head list;
> @@ -905,44 +904,26 @@ static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
> return ret;
> }
>
> -static ssize_t cache_slow_downcall(const char __user *buf,
> - size_t count, struct cache_detail *cd)
> -{
> - static char write_buf[8192]; /* protected by queue_io_mutex */
> - ssize_t ret = -EINVAL;
> -
> - if (count >= sizeof(write_buf))
> - goto out;
> - mutex_lock(&queue_io_mutex);
> - ret = cache_do_downcall(write_buf, buf, count, cd);
> - mutex_unlock(&queue_io_mutex);
> -out:
> - return ret;
> -}
> -
> static ssize_t cache_downcall(struct address_space *mapping,
> const char __user *buf,
> size_t count, struct cache_detail *cd)
> {
> - struct page *page;
> - char *kaddr;
> + char *write_buf;
> ssize_t ret = -ENOMEM;
>
> - if (count >= PAGE_SIZE)
> - goto out_slow;
> + if (count >= 32768) { /* 32k is max userland buffer, lets check anyway */
> + ret = -EINVAL;
> + goto out;
> + }
>
> - page = find_or_create_page(mapping, 0, GFP_KERNEL);
> - if (!page)
> - goto out_slow;
> + write_buf = kvmalloc(count + 1, GFP_KERNEL);
> + if (!write_buf)
> + goto out;
>
> - kaddr = kmap(page);
> - ret = cache_do_downcall(kaddr, buf, count, cd);
> - kunmap(page);
> - unlock_page(page);
> - put_page(page);
> + ret = cache_do_downcall(write_buf, buf, count, cd);
> + kvfree(write_buf);
> +out:
> return ret;
> -out_slow:
> - return cache_slow_downcall(buf, count, cd);
> }
>
> static ssize_t cache_write(struct file *filp, const char __user *buf,
> --
> 2.21.0
>
--
Chuck Lever
Hi Bruce!
Thanks for comments!, i'll send a v2 with mechanical errors fixed
based on v5.10-rc5.
rgds
roberto
On Fri, Nov 27, 2020 at 5:52 PM Chuck Lever <[email protected]> wrote:
>
> Hi Roberto-
>
> I spotted some mechanical problems.
>
>
> > On Nov 27, 2020, at 11:14 AM, Roberto Bergantinos Corpas <[email protected]> wrote:
> >
> > We can simplifly code around cache_downcall unifying memory
>
> ^simplifly^simplify
>
> > allocations using kvmalloc, this have the benefit of getting rid of
>
> ^, this have^. This has
>
> > cache_slow_downcall (and queue_io_mutex), and also matches userland
> > allocation size and limits
> >
> > Signed-off-by: Roberto Bergantinos Corpas <[email protected]>
>
> Assuming Bruce is copacetic with this patch, the change looks
> appropriate for the v5.11 merge window. However, this patch
> doesn't appear to apply to v5.10-rc5. Might be because
> 27a1e8a0f79e ("sunrpc: raise kernel RPC channel buffer size")
> was already merged?
>
>
> > ---
> > net/sunrpc/cache.c | 41 +++++++++++------------------------------
> > 1 file changed, 11 insertions(+), 30 deletions(-)
> >
> > diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
> > index baef5ee43dbb..1347ecae9c84 100644
> > --- a/net/sunrpc/cache.c
> > +++ b/net/sunrpc/cache.c
> > @@ -777,7 +777,6 @@ void cache_clean_deferred(void *owner)
> > */
> >
> > static DEFINE_SPINLOCK(queue_lock);
> > -static DEFINE_MUTEX(queue_io_mutex);
> >
> > struct cache_queue {
> > struct list_head list;
> > @@ -905,44 +904,26 @@ static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
> > return ret;
> > }
> >
> > -static ssize_t cache_slow_downcall(const char __user *buf,
> > - size_t count, struct cache_detail *cd)
> > -{
> > - static char write_buf[8192]; /* protected by queue_io_mutex */
> > - ssize_t ret = -EINVAL;
> > -
> > - if (count >= sizeof(write_buf))
> > - goto out;
> > - mutex_lock(&queue_io_mutex);
> > - ret = cache_do_downcall(write_buf, buf, count, cd);
> > - mutex_unlock(&queue_io_mutex);
> > -out:
> > - return ret;
> > -}
> > -
> > static ssize_t cache_downcall(struct address_space *mapping,
> > const char __user *buf,
> > size_t count, struct cache_detail *cd)
> > {
> > - struct page *page;
> > - char *kaddr;
> > + char *write_buf;
> > ssize_t ret = -ENOMEM;
> >
> > - if (count >= PAGE_SIZE)
> > - goto out_slow;
> > + if (count >= 32768) { /* 32k is max userland buffer, lets check anyway */
> > + ret = -EINVAL;
> > + goto out;
> > + }
> >
> > - page = find_or_create_page(mapping, 0, GFP_KERNEL);
> > - if (!page)
> > - goto out_slow;
> > + write_buf = kvmalloc(count + 1, GFP_KERNEL);
> > + if (!write_buf)
> > + goto out;
> >
> > - kaddr = kmap(page);
> > - ret = cache_do_downcall(kaddr, buf, count, cd);
> > - kunmap(page);
> > - unlock_page(page);
> > - put_page(page);
> > + ret = cache_do_downcall(write_buf, buf, count, cd);
> > + kvfree(write_buf);
> > +out:
> > return ret;
> > -out_slow:
> > - return cache_slow_downcall(buf, count, cd);
> > }
> >
> > static ssize_t cache_write(struct file *filp, const char __user *buf,
> > --
> > 2.21.0
> >
>
> --
> Chuck Lever
>
>
>