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Date: 3 Mar 2014 16:03:59 -0500 From: "George Spelvin" <linux@...izon.com> To: torvalds@...ux-foundation.org Cc: linux@...izon.com, linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, viro@...IV.linux.org.uk Subject: Re: Update of file offset on write() etc. is non-atomic with I/O > struct fd { > struct file *file; > - int need_put; > + unsigned need_put:1, need_pos_unlock:1; > }; Since we're rounding up to 2*sizeof(struct file *) anyway, is this a case where wasting space on a couple of char (or bool) flags would generate better code than a bitfield? In particular, the code to set need_pos_unlock (which will be executed each read/write for most files) is messy in the bitfield case. A byte store is much cleaner. (If you want to use bits, why not use the two lsbits of the file pointer for the purpose? That would save a lot of space.) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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