Re: [PATCH] msi: Only keep one msi_desc in each slab entry.

[Pekka J Enberg <penberg@cs.Helsinki.FI>]

On Tue, 11 Jul 2006, Eric W. Biederman wrote:
> Please look at what the code changes.
> Please recognize how very bad the current code is behaving.

Yes, there's plenty of slab confusion going on.

On Tue, 11 Jul 2006, Eric W. Biederman wrote:
> As for the rest sure go ahead and create a patch to address it
> but that really is a separate issue and thus a separate patch.
> 
> I'm just trying to keep the kernel from calling BUG_ON the first
> time a msi irq is allocated on a kernel with a maximum NR_CPUS
> configuration, and from wasting memory the rest of the time.
> 
> Or you know how bad the msi code is when every patch to fix a major
> issue is followed up comments on how to improve the code even further.

Ok.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
---

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 36bc7c4..77b08ee 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -45,16 +45,11 @@ msi_register(struct msi_ops *ops)
 	return 0;
 }
 
-static void msi_cache_ctor(void *p, kmem_cache_t *cache, unsigned long flags)
-{
-	memset(p, 0, NR_IRQS * sizeof(struct msi_desc));
-}
-
 static int msi_cache_init(void)
 {
 	msi_cachep = kmem_cache_create("msi_cache",
-			NR_IRQS * sizeof(struct msi_desc),
-		       	0, SLAB_HWCACHE_ALIGN, msi_cache_ctor, NULL);
+			sizeof(struct msi_desc),
+		       	0, SLAB_HWCACHE_ALIGN, NULL, NULL);
 	if (!msi_cachep)
 		return -ENOMEM;
 
@@ -402,11 +397,10 @@ static struct msi_desc* alloc_msi_entry(
 {
 	struct msi_desc *entry;
 
-	entry = kmem_cache_alloc(msi_cachep, SLAB_KERNEL);
+	entry = kmem_cache_zalloc(msi_cachep, GFP_KERNEL);
 	if (!entry)
 		return NULL;
 
-	memset(entry, 0, sizeof(struct msi_desc));
 	entry->link.tail = entry->link.head = 0;	/* single message */
 	entry->dev = NULL;
 
-
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