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iov_iter_get_pages(): sanity-check arguments 

zero maxpages is bogus, but best treated as "just return 0";
NULL pages, OTOH, should be treated as a hard bug.

get rid of now completely useless checks in xarray_get_pages{,_alloc}().

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2022-06-17 15:15:14 -04:00
parent 91329559eb
commit c81ce28df5
1 changed files with 2 additions and 7 deletions
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9
lib/iov_iter.c
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@ -1368,9 +1368,6 @@ static ssize_t iter_xarray_get_pages(struct iov_iter *i,
size_t size = maxsize; size_t size = maxsize;
loff_t pos; loff_t pos;
if (!size || !maxpages)
return 0;
pos = i->xarray_start + i->iov_offset; pos = i->xarray_start + i->iov_offset;
index = pos >> PAGE_SHIFT; index = pos >> PAGE_SHIFT;
offset = pos & ~PAGE_MASK; offset = pos & ~PAGE_MASK;
@ -1440,10 +1437,11 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
if (maxsize > i->count) if (maxsize > i->count)
maxsize = i->count; maxsize = i->count;
if (!maxsize) if (!maxsize || !maxpages)
return 0; return 0;
if (maxsize > MAX_RW_COUNT) if (maxsize > MAX_RW_COUNT)
maxsize = MAX_RW_COUNT; maxsize = MAX_RW_COUNT;
BUG_ON(!pages);
if (likely(user_backed_iter(i))) { if (likely(user_backed_iter(i))) {
unsigned int gup_flags = 0; unsigned int gup_flags = 0;
@ -1522,9 +1520,6 @@ static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i,
size_t size = maxsize; size_t size = maxsize;
loff_t pos; loff_t pos;
if (!size)
return 0;
pos = i->xarray_start + i->iov_offset; pos = i->xarray_start + i->iov_offset;
index = pos >> PAGE_SHIFT; index = pos >> PAGE_SHIFT;
offset = pos & ~PAGE_MASK; offset = pos & ~PAGE_MASK;