From: Serge Semin Sergey.Semin@baikalelectronics.ru
[ Upstream commit f829230dd51974c1f4478900ed30bb77ba530b40 ]
In accordance with [1] the DMA-able memory buffers must be cacheline-aligned otherwise the cache writing-back and invalidation performed during the mapping may cause the adjacent data being lost. It's specifically required for the DMA-noncoherent platforms [2]. Seeing the opal_dev.{cmd,resp} buffers are implicitly used for DMAs in the NVME and SCSI/SD drivers in framework of the nvme_sec_submit() and sd_sec_submit() methods respectively they must be cacheline-aligned to prevent the denoted problem. One of the option to guarantee that is to kmalloc the buffers [2]. Let's explicitly allocate them then instead of embedding into the opal_dev structure instance.
Note this fix was inspired by the commit c94b7f9bab22 ("nvme-hwmon: kmalloc the NVME SMART log buffer").
[1] Documentation/core-api/dma-api.rst [2] Documentation/core-api/dma-api-howto.rst
Fixes: 455a7b238cd6 ("block: Add Sed-opal library") Signed-off-by: Serge Semin Sergey.Semin@baikalelectronics.ru Reviewed-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20221107203944.31686-1-Sergey.Semin@baikalelectron... Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/sed-opal.c | 32 ++++++++++++++++++++++++++++---- 1 file changed, 28 insertions(+), 4 deletions(-)
diff --git a/block/sed-opal.c b/block/sed-opal.c index 119640897293..9651c40e093a 100644 --- a/block/sed-opal.c +++ b/block/sed-opal.c @@ -94,8 +94,8 @@ struct opal_dev { u64 lowest_lba;
size_t pos; - u8 cmd[IO_BUFFER_LENGTH]; - u8 resp[IO_BUFFER_LENGTH]; + u8 *cmd; + u8 *resp;
struct parsed_resp parsed; size_t prev_d_len; @@ -2028,6 +2028,8 @@ void free_opal_dev(struct opal_dev *dev) if (!dev) return; clean_opal_dev(dev); + kfree(dev->resp); + kfree(dev->cmd); kfree(dev); } EXPORT_SYMBOL(free_opal_dev); @@ -2040,16 +2042,38 @@ struct opal_dev *init_opal_dev(void *data, sec_send_recv *send_recv) if (!dev) return NULL;
+ /* + * Presumably DMA-able buffers must be cache-aligned. Kmalloc makes + * sure the allocated buffer is DMA-safe in that regard. + */ + dev->cmd = kmalloc(IO_BUFFER_LENGTH, GFP_KERNEL); + if (!dev->cmd) + goto err_free_dev; + + dev->resp = kmalloc(IO_BUFFER_LENGTH, GFP_KERNEL); + if (!dev->resp) + goto err_free_cmd; + INIT_LIST_HEAD(&dev->unlk_lst); mutex_init(&dev->dev_lock); dev->data = data; dev->send_recv = send_recv; if (check_opal_support(dev) != 0) { pr_debug("Opal is not supported on this device\n"); - kfree(dev); - return NULL; + goto err_free_resp; } return dev; + +err_free_resp: + kfree(dev->resp); + +err_free_cmd: + kfree(dev->cmd); + +err_free_dev: + kfree(dev); + + return NULL; } EXPORT_SYMBOL(init_opal_dev);