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Code Issues Releases Activity

Handle sf_buf_alloc() returning null. This can happen if the

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process takes a signal while waiting for an sf_buf to become available.

Reviewed by: alc
This commit is contained in:
Andrew Gallatin 2004-01-17 21:16:51 +00:00
parent 90165ba56f
commit 1c318b9665
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=124639
1 changed files with 18 additions and 9 deletions
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27
sys/kern/uipc_cow.c
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@ -60,18 +60,12 @@ __FBSDID("$FreeBSD$");
struct netsend_cow_stats {
int attempted;
int fail_not_mapped;
int fail_wired;
int fail_not_anon;
int fail_pmap_cow;
int fail_pg_error;
int fail_kva;
int free_post_exit;
int fail_sf_buf;
int success;
int iodone;
int freed;
};
static struct netsend_cow_stats socow_stats = {0,0,0,0,0,0,0,0,0,0,0};
static struct netsend_cow_stats socow_stats;
static void socow_iodone(void *addr, void *args);
@ -141,7 +135,22 @@ socow_setup(struct mbuf *m0, struct uio *uio)
* Allocate an sf buf
*/
sf = sf_buf_alloc(pp);
if (!sf) {
vm_page_lock_queues();
vm_page_cowclear(pp);
vm_page_unwire(pp, 0);
/*
* Check for the object going away on us. This can
* happen since we don't hold a reference to it.
* If so, we're responsible for freeing the page.
*/
if (pp->wire_count == 0 && pp->object == NULL)
vm_page_free(pp);
vm_page_unlock_queues();
socow_stats.fail_sf_buf++;
splx(s);
return(0);
}
/*
* attach to mbuf
*/