Date: Mon, 3 Nov 2014 07:46:51 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r274017 - head/sys/kern Message-ID: <201411030746.sA37kpPu037113@svn.freebsd.org>
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Author: mjg Date: Mon Nov 3 07:46:51 2014 New Revision: 274017 URL: https://svnweb.freebsd.org/changeset/base/274017 Log: Provide an on-stack temporary buffer for small ioctl requests. Modified: head/sys/kern/sys_generic.c Modified: head/sys/kern/sys_generic.c ============================================================================== --- head/sys/kern/sys_generic.c Mon Nov 3 07:18:42 2014 (r274016) +++ head/sys/kern/sys_generic.c Mon Nov 3 07:46:51 2014 (r274017) @@ -649,6 +649,7 @@ sys_ioctl(struct thread *td, struct ioct u_long com; int arg, error; u_int size; + u_char smalldata[128]; caddr_t data; if (uap->com > 0xffffffff) { @@ -680,17 +681,18 @@ sys_ioctl(struct thread *td, struct ioct arg = (intptr_t)uap->data; data = (void *)&arg; size = 0; - } else - data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK); + } else { + if (size <= sizeof(smalldata)) + data = smalldata; + else + data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK); + } } else data = (void *)&uap->data; if (com & IOC_IN) { error = copyin(uap->data, data, (u_int)size); - if (error) { - if (size > 0) - free(data, M_IOCTLOPS); - return (error); - } + if (error != 0) + goto out; } else if (com & IOC_OUT) { /* * Zero the buffer so the user always @@ -704,7 +706,8 @@ sys_ioctl(struct thread *td, struct ioct if (error == 0 && (com & IOC_OUT)) error = copyout(data, uap->data, (u_int)size); - if (size > 0) +out: + if (size > 0 && data != (caddr_t)&smalldata) free(data, M_IOCTLOPS); return (error); }
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