adulau/aha
1
0
Fork 0
mirror of https://github.com/adulau/aha.git synced 2024-12-28 03:36:19 +00:00
Code Issues Projects Releases Packages Wiki Activity

splice: fix repeated kmap()'s in default_file_splice_read()

Browse source 
We cannot reliably map more than one page at the time, or we risk
deadlocking. Just allocate the pages from low mem instead.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe 2009-05-13 08:35:35 +02:00
parent 2b1ccc0ee9
commit 4f23122858
1 changed files with 4 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
fs/splice.c
View file

@ -580,13 +580,13 @@ ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
for (i = 0; i < nr_pages && i < PIPE_BUFFERS && len; i++) {
struct page *page;
page = alloc_page(GFP_HIGHUSER);
page = alloc_page(GFP_USER);
error = -ENOMEM;
if (!page)
goto err;
this_len = min_t(size_t, len, PAGE_CACHE_SIZE - offset);
vec[i].iov_base = (void __user *) kmap(page);
vec[i].iov_base = (void __user *) page_address(page);
vec[i].iov_len = this_len;
pages[i] = page;
spd.nr_pages++;
@ -604,7 +604,6 @@ ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
nr_freed = 0;
for (i = 0; i < spd.nr_pages; i++) {
kunmap(pages[i]);
this_len = min_t(size_t, vec[i].iov_len, res);
partial[i].offset = 0;
partial[i].len = this_len;
@ -624,10 +623,9 @@ ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
return res;
err:
for (i = 0; i < spd.nr_pages; i++) {
kunmap(pages[i]);
for (i = 0; i < spd.nr_pages; i++)
__free_page(pages[i]);
}
return error;
}
EXPORT_SYMBOL(default_file_splice_read);