From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: [PATCH v14 14/74] xarray: Extract entries from an XArray Date: Sat, 16 Jun 2018 18:59:52 -0700 Message-ID: <20180617020052.4759-15-willy@infradead.org> References: <20180617020052.4759-1-willy@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=References:In-Reply-To:Message-Id:Date:Subject:Cc: To:From:Sender:Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=6CtH22NpoaemDSFVaBuH/UKCnAIo12i5SDA7CsPpPB8=; b=mX5zunOZPK8lus927oYcORrGDo 7NJtHR24AR76NEchYkiH8kzz9lZYlvx8kP8QpH2RSvNspPHnpchh6nMZzv3MBqtyOwczSwZ02ZB5Y wvPHODR25u4QbkkwLCJNVK36fRKqbq1QYoz9rU6EwaHF+UCND9yMpW/5wWQV9oq6Sskc=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To :MIME-Version:Content-Type:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=6CtH22NpoaemDSFVaBuH/UKCnAIo12i5SDA7CsPpPB8=; b=foh1P8nZUnSRHIHhSIRj89wEEj CBP+awcX+b7sfOIQF5vLsDh+3B6xFYbgCtmIpwBzwAfp6JC0tpg1iqdiKDC5PoFRngLLjhtFHCt/u njauXCaq9K5f/PaN1VX0ZSPRmM7QzkuoY79ELh2bsFC5FoTEV7z/0UYzrzrR3ku26yjU=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=6CtH22NpoaemDSFVaBuH/UKCnAIo12i5SDA7CsPpPB8=; b=enZlbfI9wXXz6+EBEkFiy9m/k kt+C1t9v+DOjsgRjSlROOtXSExB0JfbGElKzRRlkpDixFmAsj7NqoYl2vkaNRaAV9e2qsBLbawMd7 2V+NPrpcpZr6Tz9vH6txcgm1gsZQEthoYzoWVpuIbZN9iKx8Nczisl6Kf7ODKpnWM5U4nNqJUzKQU k2dxk7v2a30hWRXlDFVIobiPkbwfGy5H5+5On4MFGEIG4gDqydppCgcT8oHofRynWzWHq3ynIWJKE yI4DbKG1dLpTYowlYpBvwZBWXNe7JCH1ajp+0EW+pTITfO03ovzN3TENi+EQ8pMTkW4/YaYTdvDrE 75myFGVhg==; In-Reply-To: <20180617020052.4759-1-willy@infradead.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: linux-nilfs@vger.kernel.org, Jan Kara , Jeff Layton , Jaegeuk Kim , Matthew Wilcox , linux-f2fs-devel@lists.sourceforge.net, Nicholas Piggin , Ryusuke Konishi , Lukas Czerner , Ross Zwisler , Christoph Hellwig , Goldwyn Rodrigues The xa_extract function combines the functionality of radix_tree_gang_lookup() and radix_tree_gang_lookup_tagged(). It extracts entries matching the specified filter into a normal array. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 2 ++ lib/xarray.c | 80 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 82 insertions(+) diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 0790b3b098f0..6f398732b664 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -227,6 +227,8 @@ void *xa_find(struct xarray *xa, unsigned long *index, unsigned long max, xa_tag_t) __attribute__((nonnull(2))); void *xa_find_after(struct xarray *xa, unsigned long *index, unsigned long max, xa_tag_t) __attribute__((nonnull(2))); +unsigned int xa_extract(struct xarray *, void **dst, unsigned long start, + unsigned long max, unsigned int n, xa_tag_t); /** * xa_init() - Initialise an empty XArray. diff --git a/lib/xarray.c b/lib/xarray.c index 8756ca22363e..1e15ead40d78 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1413,6 +1413,86 @@ void *xa_find_after(struct xarray *xa, unsigned long *indexp, } EXPORT_SYMBOL(xa_find_after); +static unsigned int xas_extract_present(struct xa_state *xas, void **dst, + unsigned long max, unsigned int n) +{ + void *entry; + unsigned int i = 0; + + rcu_read_lock(); + xas_for_each(xas, entry, max) { + if (xas_retry(xas, entry)) + continue; + dst[i++] = entry; + if (i == n) + break; + } + rcu_read_unlock(); + + return i; +} + +static unsigned int xas_extract_tag(struct xa_state *xas, void **dst, + unsigned long max, unsigned int n, xa_tag_t tag) +{ + void *entry; + unsigned int i = 0; + + rcu_read_lock(); + xas_for_each_tagged(xas, entry, max, tag) { + if (xas_retry(xas, entry)) + continue; + dst[i++] = entry; + if (i == n) + break; + } + rcu_read_unlock(); + + return i; +} + +/** + * xa_extract() - Copy selected entries from the XArray into a normal array. + * @xa: The source XArray to copy from. + * @dst: The buffer to copy entries into. + * @start: The first index in the XArray eligible to be selected. + * @max: The last index in the XArray eligible to be selected. + * @n: The maximum number of entries to copy. + * @filter: Selection criterion. + * + * Copies up to @n entries that match @filter from the XArray. The + * copied entries will have indices between @start and @max, inclusive. + * + * The @filter may be an XArray tag value, in which case entries which are + * tagged with that tag will be copied. It may also be %XA_PRESENT, in + * which case non-NULL entries will be copied. + * + * The entries returned may not represent a snapshot of the XArray at a + * moment in time. For example, if another thread stores to index 5, then + * index 10, calling xa_extract() may return the old contents of index 5 + * and the new contents of index 10. Indices not modified while this + * function is running will not be skipped. + * + * If you need stronger guarantees, holding the xa_lock across calls to this + * function will prevent concurrent modification. + * + * Context: Any context. Takes and releases the RCU lock. + * Return: The number of entries copied. + */ +unsigned int xa_extract(struct xarray *xa, void **dst, unsigned long start, + unsigned long max, unsigned int n, xa_tag_t filter) +{ + XA_STATE(xas, xa, start); + + if (!n) + return 0; + + if ((__force unsigned int)filter < XA_MAX_TAGS) + return xas_extract_tag(&xas, dst, max, n, filter); + return xas_extract_present(&xas, dst, max, n); +} +EXPORT_SYMBOL(xa_extract); + #ifdef XA_DEBUG void xa_dump_node(const struct xa_node *node) { -- 2.17.1 ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot