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authorDavid Howells <dhowells@redhat.com>2021-04-25 22:02:38 +0100
committerDavid Howells <dhowells@redhat.com>2021-04-26 22:55:12 +0100
commit3d14ec1fe61aebe3da85a9b8f2c3d61e43d522e6 (patch)
treebb6b15242a45a6e6fc08d4e12fd469b0ee3f4565
parent26aaeffcafe6cbb7c3978fa6ed7555122f8c9f8c (diff)
downloadlinux-3d14ec1fe61aebe3da85a9b8f2c3d61e43d522e6.tar.gz
iov_iter: Four fixes for ITER_XARRAY
Fix four things[1] in the patch that adds ITER_XARRAY[2]: (1) Remove the address_space struct predeclaration. This is a holdover from when it was ITER_MAPPING. (2) Fix _copy_mc_to_iter() so that the xarray segment updates count and iov_offset in the iterator before returning. (3) Fix iov_iter_alignment() to not loop in the xarray case. Because the middle pages are all whole pages, only the end pages need be considered - and this can be reduced to just looking at the start position in the xarray and the iteration size. (4) Fix iov_iter_advance() to limit the size of the advance to no more than the remaining iteration size. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Jeff Layton <jlayton@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com> Link: https://lore.kernel.org/r/YIVrJT8GwLI0Wlgx@zeniv-ca.linux.org.uk [1] Link: https://lore.kernel.org/r/161918448151.3145707.11541538916600921083.stgit@warthog.procyon.org.uk [2]
-rw-r--r--include/linux/uio.h1
-rw-r--r--lib/iov_iter.c5
2 files changed, 5 insertions, 1 deletions
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 5f5ffc45d4aa..d3ec87706d75 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -10,7 +10,6 @@
#include <uapi/linux/uio.h>
struct page;
-struct address_space;
struct pipe_inode_info;
struct kvec {
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 44fa726a8323..61228a6c69f8 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -791,6 +791,8 @@ size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
curr_addr = (unsigned long) from;
bytes = curr_addr - s_addr - rem;
rcu_read_unlock();
+ i->iov_offset += bytes;
+ i->count -= bytes;
return bytes;
}
})
@@ -1147,6 +1149,7 @@ void iov_iter_advance(struct iov_iter *i, size_t size)
return;
}
if (unlikely(iov_iter_is_xarray(i))) {
+ size = min(size, i->count);
i->iov_offset += size;
i->count -= size;
return;
@@ -1346,6 +1349,8 @@ unsigned long iov_iter_alignment(const struct iov_iter *i)
return size | i->iov_offset;
return size;
}
+ if (unlikely(iov_iter_is_xarray(i)))
+ return (i->xarray_start + i->iov_offset) | i->count;
iterate_all_kinds(i, size, v,
(res |= (unsigned long)v.iov_base | v.iov_len, 0),
res |= v.bv_offset | v.bv_len,