[uml-devel] [PATCH 09/10] Uml: use GFP_ATOMIC for allocations under spinlocks.

["Paolo 'Blaisorblade' Giarrusso" <blaisorblade@yahoo.it>]

From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>

setup_initial_poll is only called with sigio_lock() held, so use appropriate
allocation.

Also, parse_chan() can also be called when holding a spinlock (see line_open()
 -> parse_chan_pair()).

I have sporadical problems (spinlock taken twice, with spinlock debugging on
UP) which could be caused by a sequence like "take spinlock, alloc and go to
sleep, take again the spinlock in the other thread".

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
---

 arch/um/drivers/chan_kern.c |    2 +-
 arch/um/kernel/sigio_user.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c
--- a/arch/um/drivers/chan_kern.c
+++ b/arch/um/drivers/chan_kern.c
@@ -465,7 +465,7 @@ static struct chan *parse_chan(char *str
 	data = (*ops->init)(str, device, opts);
 	if(data == NULL) return(NULL);
 
-	chan = kmalloc(sizeof(*chan), GFP_KERNEL);
+	chan = kmalloc(sizeof(*chan), GFP_ATOMIC);
 	if(chan == NULL) return(NULL);
 	*chan = ((struct chan) { .list	 	= LIST_HEAD_INIT(chan->list),
 				 .primary	= 1,
diff --git a/arch/um/kernel/sigio_user.c b/arch/um/kernel/sigio_user.c
--- a/arch/um/kernel/sigio_user.c
+++ b/arch/um/kernel/sigio_user.c
@@ -340,7 +340,7 @@ static int setup_initial_poll(int fd)
 {
 	struct pollfd *p;
 
-	p = um_kmalloc(sizeof(struct pollfd));
+	p = um_kmalloc_atomic(sizeof(struct pollfd));
 	if(p == NULL){
 		printk("setup_initial_poll : failed to allocate poll\n");
 		return(-1);



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