> On Nov 27, 2020, at 1:38 PM, Roberto Bergantinos Corpas <rbergant@xxxxxxxxxx> wrote: > > We can simplify code around cache_downcall unifying memory > allocations using kvmalloc. This has 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 <rbergant@xxxxxxxxxx> Thanks, Roberto. I see from linux-nfs history that Bruce explicitly asked for this change, so applied for the next merge window. See the cel-next topic branch in: git://git.linux-nfs.org/projects/cel/cel-2.6.git or https://git.linux-nfs.org/?p=cel/cel-2.6.git;a=summary > --- > 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 20c93b68505e..1a2c1c44bb00 100644 > --- a/net/sunrpc/cache.c > +++ b/net/sunrpc/cache.c > @@ -778,7 +778,6 @@ void cache_clean_deferred(void *owner) > */ > > static DEFINE_SPINLOCK(queue_lock); > -static DEFINE_MUTEX(queue_io_mutex); > > struct cache_queue { > struct list_head list; > @@ -906,44 +905,26 @@ 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[32768]; /* 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
