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authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-04 10:39:05 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-04 10:50:14 -0800
commit736706bee3298208343a76096370e4f6a5c55915 (patch)
tree3e90fd9d540cb15ac671182d52f9a4ade8657c59 /fs/read_write.c
parent84c4e1f89fefe70554da0ab33be72c9be7994379 (diff)
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get rid of legacy 'get_ds()' function
Every in-kernel use of this function defined it to KERNEL_DS (either as an actual define, or as an inline function). It's an entirely historical artifact, and long long long ago used to actually read the segment selector valueof '%ds' on x86. Which in the kernel is always KERNEL_DS. Inspired by a patch from Jann Horn that just did this for a very small subset of users (the ones in fs/), along with Al who suggested a script. I then just took it to the logical extreme and removed all the remaining gunk. Roughly scripted with git grep -l '(get_ds())' -- :^tools/ | xargs sed -i 's/(get_ds())/(KERNEL_DS)/' git grep -lw 'get_ds' -- :^tools/ | xargs sed -i '/^#define get_ds()/d' plus manual fixups to remove a few unusual usage patterns, the couple of inline function cases and to fix up a comment that had become stale. The 'get_ds()' function remains in an x86 kvm selftest, since in user space it actually does something relevant. Inspired-by: Jann Horn <jannh@google.com> Inspired-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index ff3c5e6f87cf..30df848b7451 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -426,7 +426,7 @@ ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
ssize_t result;
old_fs = get_fs();
- set_fs(get_ds());
+ set_fs(KERNEL_DS);
/* The cast to a user pointer is valid due to the set_fs() */
result = vfs_read(file, (void __user *)buf, count, pos);
set_fs(old_fs);
@@ -499,7 +499,7 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t
return -EINVAL;
old_fs = get_fs();
- set_fs(get_ds());
+ set_fs(KERNEL_DS);
p = (__force const char __user *)buf;
if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
@@ -521,7 +521,7 @@ ssize_t kernel_write(struct file *file, const void *buf, size_t count,
ssize_t res;
old_fs = get_fs();
- set_fs(get_ds());
+ set_fs(KERNEL_DS);
/* The cast to a user pointer is valid due to the set_fs() */
res = vfs_write(file, (__force const char __user *)buf, count, pos);
set_fs(old_fs);