Kernel/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-12-29 17:25:38 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

mm: shmem: fallback to page size splice if large folio has poisoned pages

Browse Source 
The tmpfs has already supported the PMD-sized large folios, and splice()
can not read any pages if the large folio has a poisoned page, which is
not good as Matthew pointed out in a previous email[1]:

"so if we have hwpoison set on one page in a folio, we now can't read
bytes from any page in the folio?  That seems like we've made a bad
situation worse."

Thus add a fallback to the PAGE_SIZE splice() still allows reading normal
pages if the large folio has hwpoisoned pages.

[1] https://lore.kernel.org/all/Zw_d0EVAJkpNJEbA@casper.infradead.org/

[baolin.wang@linux.alibaba.com: code layout cleaup, per dhowells]
  Link: https://lkml.kernel.org/r/32dd938c-3531-49f7-93e4-b7ff21fec569@linux.alibaba.com
Link: https://lkml.kernel.org/r/e3737fbd5366c4de4337bf5f2044817e77a5235b.1729915173.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Baolin Wang 2024-10-26 21:51:52 +08:00 committed by Andrew Morton
parent 477327e106
commit 729881ffd3
1 changed files with 30 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
mm/shmem.c
View File

@ -3288,11 +3288,16 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
len = min_t(size_t, len, npages * PAGE_SIZE);
do {
bool fallback_page_splice = false;
struct page *page = NULL;
pgoff_t index;
size_t size;
if (*ppos >= i_size_read(inode))
break;
error = shmem_get_folio(inode, *ppos / PAGE_SIZE, 0, &folio,
SGP_READ);
index = *ppos >> PAGE_SHIFT;
error = shmem_get_folio(inode, index, 0, &folio, SGP_READ);
if (error) {
if (error == -EINVAL)
error = 0;
@ -3301,12 +3306,15 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
if (folio) {
folio_unlock(folio);
if (folio_test_hwpoison(folio) ||
(folio_test_large(folio) &&
folio_test_has_hwpoisoned(folio))) {
page = folio_file_page(folio, index);
if (PageHWPoison(page)) {
error = -EIO;
break;
}
if (folio_test_large(folio) &&
folio_test_has_hwpoisoned(folio))
fallback_page_splice = true;
}
/*
@ -3320,7 +3328,17 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
isize = i_size_read(inode);
if (unlikely(*ppos >= isize))
break;
part = min_t(loff_t, isize - *ppos, len);
/*
* Fallback to PAGE_SIZE splice if the large folio has hwpoisoned
* pages.
*/
size = len;
if (unlikely(fallback_page_splice)) {
size_t offset = *ppos & ~PAGE_MASK;
size = umin(size, PAGE_SIZE - offset);
}
part = min_t(loff_t, isize - *ppos, size);
if (folio) {
/*
@ -3328,8 +3346,12 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
* virtual addresses, take care about potential aliasing
* before reading the page on the kernel side.
*/
if (mapping_writably_mapped(mapping))
flush_dcache_folio(folio);
if (mapping_writably_mapped(mapping)) {
if (likely(!fallback_page_splice))
flush_dcache_folio(folio);
else
flush_dcache_page(page);
}
folio_mark_accessed(folio);
/*
* Ok, we have the page, and it's up-to-date, so we can