7dc3bfcb4c
In some scenarios, if too many commands are issued by nvme command in the same time by user tasks, this may exhaust all tags of admin_q. If a reset (nvme reset or IO timeout) occurs before these commands finish, reconnect routine may fail to update nvme regs due to insufficient tags, which will cause kernel hang forever. In order to workaround this issue, maybe we can let reg_read32()/reg_read64()/reg_write32() use reserved tags. This maybe safe for nvmf: 1. For the disable ctrl path, we will not issue connect command 2. For the enable ctrl / fw activate path, since connect and reg_xx() are called serially. So the reserved tags may still be enough while reg_xx() use reserved tags. Signed-off-by: Chunguang Xu <chunguang.xu@shopee.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Keith Busch <kbusch@kernel.org>
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 reStructuredText 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.