Messages in this thread | | | From | "Tian, Kevin" <> | Subject | RE: [PATCH v17 3/3] vfio/nvgrace-gpu: Add vfio pci variant module for grace hopper | Date | Thu, 8 Feb 2024 07:21:40 +0000 |
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> From: Ankit Agrawal <ankita@nvidia.com> > Sent: Thursday, February 8, 2024 3:13 PM > >> > + * Determine how many bytes to be actually read from the > >> > device memory. > >> > + * Read request beyond the actual device memory size is > >> > filled with ~0, > >> > + * while those beyond the actual reported size is skipped. > >> > + */ > >> > + if (offset >= memregion->memlength) > >> > + mem_count = 0; > >> > >> If mem_count == 0, going through nvgrace_gpu_map_and_read() is not > >> necessary. > > > > Harmless, other than the possibly unnecessary call through to > > nvgrace_gpu_map_device_mem(). Maybe both > nvgrace_gpu_map_and_read() > > and nvgrace_gpu_map_and_write() could conditionally return 0 as their > > first operation when !mem_count. Thanks, > > > >Alex > > IMO, this seems like adding too much code to reduce the call length for a > very specific case. If there aren't any strong opinion on this, I'm planning to > leave this code as it is.
a slight difference. if mem_count==0 the result should always succeed no matter nvgrace_gpu_map_device_mem() succeeds or not. Of course if it fails it's already a big problem probably nobody cares about the subtle difference when reading non-exist range.
but regarding to readability it's still clearer:
if (mem_count) nvgrace_gpu_map_and_read();
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