net: skbuff: fix spelling errors

Correct spelling as reported by codespell.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20231213043511.10357-1-rdunlap@infradead.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/skbuff.h

@@ -1069,7 +1069,7 @@ struct sk_buff {
 	refcount_t		users;
 
 #ifdef CONFIG_SKB_EXTENSIONS
-	/* only useable after checking ->active_extensions != 0 */
+	/* only usable after checking ->active_extensions != 0 */
 	struct skb_ext		*extensions;
 #endif
 };
@@ -3311,7 +3311,7 @@ static inline struct page *__dev_alloc_pages(gfp_t gfp_mask,
 					     unsigned int order)
 {
 	/* This piece of code contains several assumptions.
-	 * 1.  This is for device Rx, therefor a cold page is preferred.
+	 * 1.  This is for device Rx, therefore a cold page is preferred.
 	 * 2.  The expectation is the user wants a compound page.
 	 * 3.  If requesting a order 0 page it will not be compound
 	 *     due to the check to see if order has a value in prep_new_page
@@ -4247,7 +4247,7 @@ static inline bool __skb_metadata_differs(const struct sk_buff *skb_a,
 {
 	const void *a = skb_metadata_end(skb_a);
 	const void *b = skb_metadata_end(skb_b);
-	/* Using more efficient varaiant than plain call to memcmp(). */
+	/* Using more efficient variant than plain call to memcmp(). */
 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
 	u64 diffs = 0;