Re: 78cd83e4017b - main - devclass_alloc_unit: Go back to using M_WAITOK

Hi John,

> This reverts commit 234683726708cf5212d672d676d30056d4133859.

The commit message for that change says that this allocation might be done while holding a lock, and so M_WAITOK is not valid. So then why is this change okay?

Thanks,

Ravi (rpokala@0

-----Original Message-----
From: <owner-src-committers@freebsd.org <mailto:owner-src-committers@freebsd.org>> on behalf of John Baldwin <jhb@FreeBSD.org <mailto:jhb@FreeBSD.org>>
Date: Monday, March 10, 2025 at 10:35
To: <src-committers@FreeBSD.org <mailto:src-committers@FreeBSD.org>>, <dev-commits-src-all@FreeBSD.org <mailto:dev-commits-src-all@FreeBSD.org>>, <dev-commits-src-main@FreeBSD.org <mailto:dev-commits-src-main@FreeBSD.org>>
Subject: git: 78cd83e4017b - main - devclass_alloc_unit: Go back to using M_WAITOK


The branch main has been updated by jhb:


URL: https://cgit.FreeBSD.org/src/commit/?id=78cd83e4017bccf62a291e57f0cceccf80e50423 <https://cgit.FreeBSD.org/src/commit/?id=78cd83e4017bccf62a291e57f0cceccf80e50423>


commit 78cd83e4017bccf62a291e57f0cceccf80e50423
Author: John Baldwin <jhb@FreeBSD.org <mailto:jhb@FreeBSD.org>>
AuthorDate: 2025-03-10 17:34:44 +0000
Commit: John Baldwin <jhb@FreeBSD.org <mailto:jhb@FreeBSD.org>>
CommitDate: 2025-03-10 17:34:44 +0000


devclass_alloc_unit: Go back to using M_WAITOK


This restores a change made earlier in f3d3c63442fff.


This reverts commit 234683726708cf5212d672d676d30056d4133859.


Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D49273 <https://reviews.freebsd.org/D49273>
---
sys/kern/subr_bus.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)


diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c
index 38a8cab639e4..63de61262554 100644
--- a/sys/kern/subr_bus.c
+++ b/sys/kern/subr_bus.c
@@ -1211,7 +1211,6 @@ devclass_get_sysctl_tree(devclass_t dc)
static int
devclass_alloc_unit(devclass_t dc, device_t dev, int *unitp)
{
- device_t *devices;
const char *s;
int unit = *unitp;


@@ -1268,11 +1267,8 @@ devclass_alloc_unit(devclass_t dc, device_t dev, int *unitp)
int newsize;


newsize = unit + 1;
- devices = reallocf(dc->devices,
- newsize * sizeof(*dc->devices), M_BUS, M_NOWAIT);
- if (devices == NULL)
- return (ENOMEM);
- dc->devices = devices;
+ dc->devices = reallocf(dc->devices,
+ newsize * sizeof(*dc->devices), M_BUS, M_WAITOK);
memset(dc->devices + dc->maxunit, 0,
sizeof(device_t) * (newsize - dc->maxunit));
dc->maxunit = newsize;