Date: Sun, 07 Jan 2018 19:30:04 +0100 From: "Kristof Provost" <kp@FreeBSD.org> To: rgrimes@freebsd.org Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r327676 - head/sys/compat/linuxkpi/common/include/linux Message-ID: <219974D5-0240-49D9-8DE4-C1FBCEF74776@FreeBSD.org> In-Reply-To: <201801071802.w07I2YEB017699@pdx.rh.CN85.dnsmgr.net> References: <201801071802.w07I2YEB017699@pdx.rh.CN85.dnsmgr.net>
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On 7 Jan 2018, at 19:02, Rodney W. Grimes wrote: > [ Charset UTF-8 unsupported, converting... ] >> Author: kp >> Date: Sun Jan 7 13:39:12 2018 >> New Revision: 327676 >> URL: https://svnweb.freebsd.org/changeset/base/327676 >> >> Log: >> linuxkpi: Implement kcalloc() based on mallocarray() >> >> This means we now get integer overflow protection, which Linux code >> might expect as it is also provided by kcalloc() in Linux. >> >> Modified: >> head/sys/compat/linuxkpi/common/include/linux/slab.h >> >> Modified: head/sys/compat/linuxkpi/common/include/linux/slab.h >> ============================================================================== >> --- head/sys/compat/linuxkpi/common/include/linux/slab.h Sun Jan 7 >> 13:35:15 2018 (r327675) >> +++ head/sys/compat/linuxkpi/common/include/linux/slab.h Sun Jan 7 >> 13:39:12 2018 (r327676) >> @@ -46,7 +46,6 @@ MALLOC_DECLARE(M_KMALLOC); >> #define kzalloc(size, flags) kmalloc(size, (flags) | __GFP_ZERO) >> #define kzalloc_node(size, flags, node) kmalloc(size, (flags) | >> __GFP_ZERO) >> #define kfree_const(ptr) kfree(ptr) >> -#define kcalloc(n, size, flags) kmalloc((n) * (size), >> (flags) | __GFP_ZERO) > > Would not: > #define kcalloc(n, size, flags) mallocarray(mallocarray((n), > (size), M_KMALLOC, linux_check_m_flags((flags | __GFP_ZERO)) > work just fine, saving a call and stack use of about framesize + 32 > bytes? > > It would also work, but it’d have to be split up into multiple lines then. I thought it’d be more readable as a function. It’s an inline function, so it won’t actually use stack space in practice. Also, it used to call kmalloc(), which is also an inline function, so at worst we’ve traded one function for another. Regards, Kristof
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