CVS commit: src/sys/dev/pci

["matthew green" <mrg%netbsd.org@localhost>]

Module Name:    src
Committed By:   mrg
Date:           Thu Oct 19 23:43:40 UTC 2023

Modified Files:
        src/sys/dev/pci: if_rge.c

Log Message:
rge: properly handle mbuf allocation failures in rx interrupts

several changes that should fix crashes seen after an mbuf
allocation failure:

- create RX ring dma maps with BUS_DMA_ALLOCNOW, so that any
  future bus_dmamap_load*() call will succeed.  this avoids one
  error case in rge_newbuf(), that similar cases in eg wm(4)
  actually call panic for now (i think this idea can be copied
  into wm(4) as well.)

- extract the RX descriptor set into a common function that
  both rge_newbuf() and rge_rxeof() can both use.  it's almost
  identical to the old rge_discard_rxbuf() except it also sets
  the rge_addr (this is needed for the newbuf case.)

- move the bus_dmamap_unload() into rge_newbuf(), so that the
  existing mbuf will remain mapped until a new mbuf is allocated.
  (this part is what should fix crashes seen by wiz and Chavdar,
  as the unload follow by sync is what triggers the assert in
  x86 bus_dma.  without the assert, it will would have shortly
  triggered a page fault.)  remove the assignment to NULL for
  the rxq mbuf pointer, it is required for reload.

- add a couple of missing if_statinc() calls.

tested on amd64 and arm64.


To generate a diff of this commit:
cvs rdiff -u -r1.27 -r1.28 src/sys/dev/pci/if_rge.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.