Hi
On Tue, Mar 2, 2021 at 4:43 PM Andre Przywara andre.przywara@arm.com wrote:
At the moment the nvme_get_features() and nvme_set_features() functions carry a (somewhat misleading) comment about missing cache maintenance.
As it turns out, nvme_get_features() has no caller at all in the tree, and nvme_set_features' only user doesn't use a DMA buffer.
Mention that in the comment, and leave some breadcrumbs for the future, should those functions attract more users.
Signed-off-by: Andre Przywara andre.przywara@arm.com
Hi,
just extending the comments as this caused some confusion lately, and to keep the pointer to the NVMe spec I checked.
Cheers, Andre
drivers/nvme/nvme.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-)
diff --git a/drivers/nvme/nvme.c b/drivers/nvme/nvme.c index 5d6331ad346..3ff3d5de08e 100644 --- a/drivers/nvme/nvme.c +++ b/drivers/nvme/nvme.c @@ -481,6 +481,7 @@ int nvme_get_features(struct nvme_dev *dev, unsigned fid, unsigned nsid, dma_addr_t dma_addr, u32 *result) { struct nvme_command c;
int ret; memset(&c, 0, sizeof(c)); c.features.opcode = nvme_admin_get_features;@@ -488,12 +489,20 @@ int nvme_get_features(struct nvme_dev *dev, unsigned fid, unsigned nsid, c.features.prp1 = cpu_to_le64(dma_addr); c.features.fid = cpu_to_le32(fid);
ret = nvme_submit_admin_cmd(dev, &c, result);/*
* TODO: add cache invalidate operation when the size of* the DMA buffer is known
* TODO: Add some cache invalidation when a DMA buffer is involved* in the request, here and before the command gets submitted. The* buffer size varies by feature, also some features use a different* field in the command packet to hold the buffer address.* Section 5.21.1 (Set Features command) in the NVMe specification* details the buffer requirements for each feature.** At the moment there is no user of this function. */
return nvme_submit_admin_cmd(dev, &c, result);
return ret;}
int nvme_set_features(struct nvme_dev *dev, unsigned fid, unsigned dword11, @@ -508,8 +517,14 @@ int nvme_set_features(struct nvme_dev *dev, unsigned fid, unsigned dword11, c.features.dword11 = cpu_to_le32(dword11);
/*
* TODO: add cache flush operation when the size of* the DMA buffer is known
* TODO: Add a cache clean (aka flush) operation when a DMA buffer is* involved in the request. The buffer size varies by feature, also* some features use a different field in the command packet to hold* the buffer address. Section 5.21.1 (Set Features command) in the* NVMe specification details the buffer requirements for each* feature.* At the moment the only user of this function is not using* any DMA buffer at all. */ return nvme_submit_admin_cmd(dev, &c, result);
Reviewed-By: Michael Trimarchi michael@amarulasolutions.com
-- 2.17.5