From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Holt Date: Wed, 04 Feb 2009 00:40:59 +0000 Subject: [Patch] bte_copy of BTE_MAX_XFER trips BUG_ON. Message-Id: <20090204004059.GM8559@sgi.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: tony.luck@intel.com Cc: linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, Dean Nelson , Russ Anderson BTE_MAX_XFER is wrong. It is one greater than the number of cache lines the BTE is actually able to transfer. If you request a transfer of exactly BTE_MAX_XFER size, you trip a very cryptic BUG_ON() which should certainly be made more clear. This patch fixes that constant and also cleans up the BUG_ON()s in arch/ia64/sn/kernel/bte.c to test one condition per line. Signed-off-by: Robin Holt --- arch/ia64/include/asm/sn/bte.h | 2 +- arch/ia64/sn/kernel/bte.c | 7 ++++--- 2 files changed, 5 insertions(+), 4 deletions(-) Index: bte_max_xfer_fix/arch/ia64/include/asm/sn/bte.h =================================--- bte_max_xfer_fix.orig/arch/ia64/include/asm/sn/bte.h 2009-02-03 18:07:26.000000000 -0600 +++ bte_max_xfer_fix/arch/ia64/include/asm/sn/bte.h 2009-02-03 18:09:38.749729353 -0600 @@ -39,7 +39,7 @@ /* BTE status register only supports 16 bits for length field */ #define BTE_LEN_BITS (16) #define BTE_LEN_MASK ((1 << BTE_LEN_BITS) - 1) -#define BTE_MAX_XFER ((1 << BTE_LEN_BITS) * L1_CACHE_BYTES) +#define BTE_MAX_XFER (BTE_LEN_MASK << L1_CACHE_SHIFT) /* Define hardware */ Index: bte_max_xfer_fix/arch/ia64/sn/kernel/bte.c =================================--- bte_max_xfer_fix.orig/arch/ia64/sn/kernel/bte.c 2009-02-03 18:07:26.000000000 -0600 +++ bte_max_xfer_fix/arch/ia64/sn/kernel/bte.c 2009-02-03 18:15:42.854040475 -0600 @@ -97,9 +97,10 @@ bte_result_t bte_copy(u64 src, u64 dest, return BTE_SUCCESS; } - BUG_ON((len & L1_CACHE_MASK) || - (src & L1_CACHE_MASK) || (dest & L1_CACHE_MASK)); - BUG_ON(!(len < ((BTE_LEN_MASK + 1) << L1_CACHE_SHIFT))); + BUG_ON(len & L1_CACHE_MASK); + BUG_ON(src & L1_CACHE_MASK); + BUG_ON(dest & L1_CACHE_MASK); + BUG_ON(len > BTE_MAX_XFER); /* * Start with interface corresponding to cpu number