Re: [dpdk-dev] [PATCH v2] pci: keep API compatibility with mmap values

[Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>]

On Fri, 10 Jul 2020 22:40:34 +0200, Thomas Monjalon wrote:
> The function pci_map_resource() returns MAP_FAILED in case of error.
> When replacing the call to mmap() by rte_mem_map(),
> the error code became NULL, breaking the API.
> This function is probably not used outside of DPDK,
> but it is still a problem for two reasons:
> 	- the deprecation process was not followed
> 	- the Linux function pci_vfio_mmap_bar() is broken for i40e
> 
> The error code is reverted to the Unix value MAP_FAILED.
> Windows needs to define this special value (-1 as in Unix).
> After proper deprecation process, the API could be changed again
> if really needed.
> 
> Because of the switch from mmap() to rte_mem_map(),
> another part of the API was changed: "int additional_flags"
> are defined as "additional flags for the mapping range"
> without mentioning it was directly used in mmap().
> Currently it is directly used in rte_mem_map(),
> that's why the values rte_map_flags must be mapped (sic) on the mmap ones
> in case of Unix OS.
> 
> These are side effects of a badly defined API using Unix values.
> 
> Bugzilla ID: 503
> Fixes: 2fd3567e5425 ("pci: use OS generic memory mapping functions")
> Cc: talshn@mellanox.com
> 
> Reported-by: David Marchand <david.marchand@redhat.com>
> Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> ---
> v2: move MAP_FAILED from sys/mman.h to rte_os.h
> ---
>  drivers/bus/pci/bsd/pci.c               |  2 +-
>  drivers/bus/pci/linux/pci_uio.c         |  2 +-
>  drivers/bus/pci/linux/pci_vfio.c        |  4 ++--
>  drivers/bus/pci/pci_common_uio.c        |  2 +-
>  lib/librte_eal/include/rte_eal_paging.h | 10 ++++++++++
>  lib/librte_eal/windows/include/rte_os.h |  6 ++++++
>  lib/librte_pci/rte_pci.c                |  1 +
>  lib/librte_pci/rte_pci.h                |  2 +-
>  8 files changed, 23 insertions(+), 6 deletions(-)

Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>

No Intel NIC to test, but LGTM and compiles OK for Windows.