1 /* 2 * Copyright (c) 2009 Atheros Communications Inc. 3 * 4 * Permission to use, copy, modify, and/or distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 20 #include "ath.h" 21 22 MODULE_AUTHOR("Atheros Communications"); 23 MODULE_DESCRIPTION("Shared library for Atheros wireless LAN cards."); 24 MODULE_LICENSE("Dual BSD/GPL"); 25 26 struct sk_buff *ath_rxbuf_alloc(struct ath_common *common, 27 u32 len, 28 gfp_t gfp_mask) 29 { 30 struct sk_buff *skb; 31 u32 off; 32 33 /* 34 * Cache-line-align. This is important (for the 35 * 5210 at least) as not doing so causes bogus data 36 * in rx'd frames. 37 */ 38 39 /* Note: the kernel can allocate a value greater than 40 * what we ask it to give us. We really only need 4 KB as that 41 * is this hardware supports and in fact we need at least 3849 42 * as that is the MAX AMSDU size this hardware supports. 43 * Unfortunately this means we may get 8 KB here from the 44 * kernel... and that is actually what is observed on some 45 * systems :( */ 46 skb = __dev_alloc_skb(len + common->cachelsz - 1, gfp_mask); 47 if (skb != NULL) { 48 off = ((unsigned long) skb->data) % common->cachelsz; 49 if (off != 0) 50 skb_reserve(skb, common->cachelsz - off); 51 } else { 52 printk(KERN_ERR "skbuff alloc of size %u failed\n", len); 53 return NULL; 54 } 55 56 return skb; 57 } 58 EXPORT_SYMBOL(ath_rxbuf_alloc); 59