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dm ioctl: Simplify parameter buffer management code

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Merge the two DM_PARAMS_[KV]MALLOC flags into a single flag.

Doing so avoids the crashes seen with previous attempts to consolidate
buffer management to use kvfree() without first flagging that memory had
actually been allocated.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Bart Van Assche 2016-06-28 16:36:46 +02:00 committed by Mike Snitzer
parent 350b539328
commit 028b39e314
1 changed files with 6 additions and 12 deletions
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18
drivers/md/dm-ioctl.c
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@ -1670,8 +1670,7 @@ static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
return r; return r;
} }
#define DM_PARAMS_KMALLOC 0x0001 /* Params alloced with kmalloc */ #define DM_PARAMS_MALLOC 0x0001 /* Params allocated with kvmalloc() */
#define DM_PARAMS_VMALLOC 0x0002 /* Params alloced with vmalloc */
#define DM_WIPE_BUFFER 0x0010 /* Wipe input buffer before returning from ioctl */ #define DM_WIPE_BUFFER 0x0010 /* Wipe input buffer before returning from ioctl */
static void free_params(struct dm_ioctl *param, size_t param_size, int param_flags) static void free_params(struct dm_ioctl *param, size_t param_size, int param_flags)
@ -1679,10 +1678,8 @@ static void free_params(struct dm_ioctl *param, size_t param_size, int param_fla
if (param_flags & DM_WIPE_BUFFER) if (param_flags & DM_WIPE_BUFFER)
memset(param, 0, param_size); memset(param, 0, param_size);
if (param_flags & DM_PARAMS_KMALLOC) if (param_flags & DM_PARAMS_MALLOC)
kfree(param); kvfree(param);
if (param_flags & DM_PARAMS_VMALLOC)
vfree(param);
} }
static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kernel, static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kernel,
@ -1714,19 +1711,14 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
* Use kmalloc() rather than vmalloc() when we can. * Use kmalloc() rather than vmalloc() when we can.
*/ */
dmi = NULL; dmi = NULL;
if (param_kernel->data_size <= KMALLOC_MAX_SIZE) { if (param_kernel->data_size <= KMALLOC_MAX_SIZE)
dmi = kmalloc(param_kernel->data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); dmi = kmalloc(param_kernel->data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
if (dmi)
*param_flags |= DM_PARAMS_KMALLOC;
}
if (!dmi) { if (!dmi) {
unsigned noio_flag; unsigned noio_flag;
noio_flag = memalloc_noio_save(); noio_flag = memalloc_noio_save();
dmi = __vmalloc(param_kernel->data_size, GFP_NOIO | __GFP_HIGH | __GFP_HIGHMEM, PAGE_KERNEL); dmi = __vmalloc(param_kernel->data_size, GFP_NOIO | __GFP_HIGH | __GFP_HIGHMEM, PAGE_KERNEL);
memalloc_noio_restore(noio_flag); memalloc_noio_restore(noio_flag);
if (dmi)
*param_flags |= DM_PARAMS_VMALLOC;
} }
if (!dmi) { if (!dmi) {
@ -1735,6 +1727,8 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
return -ENOMEM; return -ENOMEM;
} }
*param_flags |= DM_PARAMS_MALLOC;
if (copy_from_user(dmi, user, param_kernel->data_size)) if (copy_from_user(dmi, user, param_kernel->data_size))
goto bad; goto bad;