handle error case

kaiwan · kaiwan · commit 5e5783e8d8b1 · 2022-12-10T18:07:00.000+05:30
diff --git a/ch9/slab_custom/slab_custom.c b/ch9/slab_custom/slab_custom.c
@@ -49,7 +49,7 @@ struct myctx {
 };
 static struct kmem_cache *gctx_cachep;
 
-static void use_our_cache(void)
+static int use_our_cache(void)
 {
 	struct myctx *obj = NULL;
 
@@ -62,6 +62,7 @@ static void use_our_cache(void)
 	obj = kmem_cache_alloc(gctx_cachep, GFP_KERNEL);
 	if (!obj) {		/* pedantic warning printk below... */
 		pr_warn("kmem_cache_alloc() failed\n");
+		return -ENOMEM;
 	}
 
 	pr_info("Our cache object (@ %pK, actual=%px) size is %u bytes; actual ksize=%zu\n",
@@ -70,6 +71,7 @@ static void use_our_cache(void)
 
 	/* free it */
 	kmem_cache_free(gctx_cachep, obj);
+	return 0;
 }
 
 /* The parameter is the pointer to the just allocated memory 'object' from

Original file line number	Diff line number	Diff line change
`@@ -49,7 +49,7 @@ struct myctx {`
`49`	`49`	`};`
`50`	`50`	`static struct kmem_cache *gctx_cachep;`
`51`	`51`
`52`		`-static void use_our_cache(void)`
	`52`	`+static int use_our_cache(void)`
`53`	`53`	`{`
`54`	`54`	`struct myctx *obj = NULL;`
`55`	`55`
`@@ -62,6 +62,7 @@ static void use_our_cache(void)`
`62`	`62`	`obj = kmem_cache_alloc(gctx_cachep, GFP_KERNEL);`
`63`	`63`	`if (!obj) { /* pedantic warning printk below... */`
`64`	`64`	`pr_warn("kmem_cache_alloc() failed\n");`
	`65`	`+ return -ENOMEM;`
`65`	`66`	`}`
`66`	`67`
`67`	`68`	`pr_info("Our cache object (@ %pK, actual=%px) size is %u bytes; actual ksize=%zu\n",`
`@@ -70,6 +71,7 @@ static void use_our_cache(void)`
`70`	`71`
`71`	`72`	`/* free it */`
`72`	`73`	`kmem_cache_free(gctx_cachep, obj);`
	`74`	`+ return 0;`
`73`	`75`	`}`
`74`	`76`
`75`	`77`	`/* The parameter is the pointer to the just allocated memory 'object' from`