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ipc: separate msg allocation from userspace copy

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Separating msg allocation enables single-block vmalloc
allocation instead.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Peter Hurley 2013-04-30 19:14:31 -07:00 • committed by Linus Torvalds
parent 3d8fa456d5
commit be5f4b335f
1 changed files with 38 additions and 14 deletions
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52
ipc/msgutil.c
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@ -44,21 +44,54 @@ struct msg_msgseg {
#define DATALEN_MSG (int)(PAGE_SIZE-sizeof(struct msg_msg)) #define DATALEN_MSG (int)(PAGE_SIZE-sizeof(struct msg_msg))
#define DATALEN_SEG (int)(PAGE_SIZE-sizeof(struct msg_msgseg)) #define DATALEN_SEG (int)(PAGE_SIZE-sizeof(struct msg_msgseg))
struct msg_msg *load_msg(const void __user *src, int len)
static struct msg_msg *alloc_msg(int len)
{ {
struct msg_msg *msg; struct msg_msg *msg;
struct msg_msgseg **pseg; struct msg_msgseg **pseg;
int err;
int alen; int alen;
alen = min(len, DATALEN_MSG); alen = min(len, DATALEN_MSG);
msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL); msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL);
if (msg == NULL) if (msg == NULL)
return ERR_PTR(-ENOMEM); return NULL;
msg->next = NULL; msg->next = NULL;
msg->security = NULL; msg->security = NULL;
len -= alen;
pseg = &msg->next;
while (len > 0) {
struct msg_msgseg *seg;
alen = min(len, DATALEN_SEG);
seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL);
if (seg == NULL)
goto out_err;
*pseg = seg;
seg->next = NULL;
pseg = &seg->next;
len -= alen;
}
return msg;
out_err:
free_msg(msg);
return NULL;
}
struct msg_msg *load_msg(const void __user *src, int len)
{
struct msg_msg *msg;
struct msg_msgseg *seg;
int err;
int alen;
msg = alloc_msg(len);
if (msg == NULL)
return ERR_PTR(-ENOMEM);
alen = min(len, DATALEN_MSG);
if (copy_from_user(msg + 1, src, alen)) { if (copy_from_user(msg + 1, src, alen)) {
err = -EFAULT; err = -EFAULT;
goto out_err; goto out_err;
@ -66,23 +99,14 @@ struct msg_msg *load_msg(const void __user *src, int len)
len -= alen; len -= alen;
src = ((char __user *)src) + alen; src = ((char __user *)src) + alen;
pseg = &msg->next; seg = msg->next;
while (len > 0) { while (len > 0) {
struct msg_msgseg *seg;
alen = min(len, DATALEN_SEG); alen = min(len, DATALEN_SEG);
seg = kmalloc(sizeof(*seg) + alen,
GFP_KERNEL);
if (seg == NULL) {
err = -ENOMEM;
goto out_err;
}
*pseg = seg;
seg->next = NULL;
if (copy_from_user(seg + 1, src, alen)) { if (copy_from_user(seg + 1, src, alen)) {
err = -EFAULT; err = -EFAULT;
goto out_err; goto out_err;
} }
pseg = &seg->next; seg = seg->next;
len -= alen; len -= alen;
src = ((char __user *)src) + alen; src = ((char __user *)src) + alen;
} }