Commit 79a92636 authored by Oleg Drokin's avatar Oleg Drokin Committed by Ben Hutchings

staging/lustre/lov: remove set_fs() call from lov_getstripe()

commit 0a33252e upstream.

lov_getstripe() calls set_fs(KERNEL_DS) so that it can handle a struct
lov_user_md pointer from user- or kernel-space.  This changes the
behavior of copy_from_user() on SPARC and may result in a misaligned
access exception which in turn oopses the kernel.  In fact the
relevant argument to lov_getstripe() is never called with a
kernel-space pointer and so changing the address limits is unnecessary
and so we remove the calls to save, set, and restore the address
limits.
Signed-off-by: default avatarJohn L. Hammond <john.hammond@intel.com>
Reviewed-on: http://review.whamcloud.com/6150
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3221Reviewed-by: default avatarAndreas Dilger <andreas.dilger@intel.com>
Reviewed-by: default avatarLi Wei <wei.g.li@intel.com>
Signed-off-by: default avatarOleg Drokin <green@linuxhacker.ru>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent d30435bd
...@@ -592,18 +592,10 @@ int lov_getstripe(struct obd_export *exp, struct lov_stripe_md *lsm, ...@@ -592,18 +592,10 @@ int lov_getstripe(struct obd_export *exp, struct lov_stripe_md *lsm,
struct lov_mds_md *lmmk = NULL; struct lov_mds_md *lmmk = NULL;
int rc, lmm_size; int rc, lmm_size;
int lum_size; int lum_size;
mm_segment_t seg;
if (!lsm) if (!lsm)
return -ENODATA; return -ENODATA;
/*
* "Switch to kernel segment" to allow copying from kernel space by
* copy_{to,from}_user().
*/
seg = get_fs();
set_fs(KERNEL_DS);
/* we only need the header part from user space to get lmm_magic and /* we only need the header part from user space to get lmm_magic and
* lmm_stripe_count, (the header part is common to v1 and v3) */ * lmm_stripe_count, (the header part is common to v1 and v3) */
lum_size = sizeof(struct lov_user_md_v1); lum_size = sizeof(struct lov_user_md_v1);
...@@ -672,6 +664,5 @@ int lov_getstripe(struct obd_export *exp, struct lov_stripe_md *lsm, ...@@ -672,6 +664,5 @@ int lov_getstripe(struct obd_export *exp, struct lov_stripe_md *lsm,
obd_free_diskmd(exp, &lmmk); obd_free_diskmd(exp, &lmmk);
out_set: out_set:
set_fs(seg);
return rc; return rc;
} }
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