[Differential] [Request, 32 lines] D3121: Don't allow malloc() to wait for resource while holding a lock in ITS

[zbb (Zbigniew Bodek)]

zbb created this revision.
zbb added reviewers: emaste, andrew, wma_semihalf.com, imp, ian.
zbb added a subscriber: freebsd-arm-list.
zbb set the repository for this revision to rS FreeBSD src repository.
Herald added subscribers: emaste, andrew, imp.

REVISION SUMMARY
  malloc() should not go to sleep in case of lack of resource while
  the kernel thread is holding a non-sleepable lock.
  - change malloc() flags to M_NOWAIT in such cases
  - implement lpi_free_chunk() routine since it will be needed
    when ITT allocation fails in its_device_alloc_locked()
  - do not increase verbosity of this code since upper layers
    will communicate an error if the interrupt setup fails
  
  Obtained from: Semihalf
  Sponsored by:  The FreeBSD Foundation

REPOSITORY
  rS FreeBSD src repository

REVISION DETAIL
  https://reviews.freebsd.org/D3121

AFFECTED FILES
  sys/arm64/arm64/gic_v3_its.c

CHANGE DETAILS
  diff --git a/sys/arm64/arm64/gic_v3_its.c b/sys/arm64/arm64/gic_v3_its.c
  --- a/sys/arm64/arm64/gic_v3_its.c
  +++ b/sys/arm64/arm64/gic_v3_its.c
  @@ -795,6 +795,26 @@
   }
   
   static void
  +lpi_free_chunk(struct gic_v3_its_softc *sc, struct lpi_chunk *lpic)
  +{
  +	int start, end;
  +	uint8_t *bitmap;
  +
  +	bitmap = (uint8_t *)sc->its_lpi_bitmap;
  +
  +	KASSERT((lpic->lpi_free == lpic->lpi_num),
  +	    ("Trying to free LPI chunk that is still in use.\n"));
  +
  +	/* First bit of this chunk in a global bitmap */
  +	start = lpic->lpi_base - GIC_FIRST_LPI;
  +	/* and last bit of this chunk... */
  +	end = start + lpic->lpi_num - 1;
  +
  +	/* Finally free this chunk */
  +	bit_nclear(bitmap, start, end);
  +}
  +
  +static void
   lpi_configure(struct gic_v3_its_softc *sc, struct its_dev *its_dev,
       uint32_t lpinum, boolean_t unmask)
   {
  @@ -1303,7 +1323,10 @@
   	devid = PCI_DEVID(pci_dev);
   
   	/* There was no previously created device. Create one now */
  -	newdev = malloc(sizeof(*newdev), M_GIC_V3_ITS, (M_WAITOK | M_ZERO));
  +	newdev = malloc(sizeof(*newdev), M_GIC_V3_ITS, (M_NOWAIT | M_ZERO));
  +	if (newdev == NULL)
  +		return (NULL);
  +
   	newdev->pci_dev = pci_dev;
   	newdev->devid = devid;
   
  @@ -1321,7 +1344,12 @@
   	 */
   	newdev->itt = (vm_offset_t)contigmalloc(
   	    roundup2(roundup2(nvecs, 2) * esize, 0x100), M_GIC_V3_ITS,
  -	    (M_WAITOK | M_ZERO), 0, ~0UL, 0x100, 0);
  +	    (M_NOWAIT | M_ZERO), 0, ~0UL, 0x100, 0);
  +	if (newdev->itt == 0) {
  +		lpi_free_chunk(sc, &newdev->lpis);
  +		free(newdev, M_GIC_V3_ITS);
  +		return (NULL);
  +	}
   
   	/*
   	 * XXX ARM64TODO: Currently all interrupts are going

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To: zbb, emaste, andrew, wma_semihalf.com, imp, ian
Cc: imp, andrew, freebsd-arm-list, emaste
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