c03fd85de2
nvme_clear_request() has a check for flag REQ_DONTPREP and it is called from nvme_init_request() and nvme_setuo_cmd(). The function nvme_init_request() is called from nvme_alloc_request() and nvme_alloc_request_qid(). From these two callers new request is allocated everytime. For newly allocated request RQF_DONTPREP is never set. Since after getting a tag, block layer sets the req->rq_flags == 0 and never sets the REQ_DONTPREP when returning the request :- nvme_alloc_request() blk_mq_alloc_request() blk_mq_rq_ctx_init() rq->rq_flags = 0 <---- nvme_alloc_request_qid() blk_mq_alloc_request_hctx() blk_mq_rq_ctx_init() rq->rq_flags = 0 <---- The block layer does set req->rq_flags but REQ_DONTPREP is not one of them and that is set by the driver. That means we can unconditinally set the REQ_DONTPREP value to the rq->rq_flags when nvme_init_request()->nvme_clear_request() is called from above two callers. Move the check for REQ_DONTPREP from nvme_clear_nvme_request() into nvme_setup_cmd(). This is needed since nvme_alloc_request() now gets called from fast path when NVMeOF target is configured with passthru backend to avoid unnecessary checks in the fast path. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.