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From: Alan Maguire <alan.maguire@oracle.com>
To: ast@kernel.org, daniel@iogearbox.net, andriin@fb.com, yhs@fb.com
Cc: linux@rasmusvillemoes.dk, andriy.shevchenko@linux.intel.com,
	pmladek@suse.com, kafai@fb.com, songliubraving@fb.com,
	john.fastabend@gmail.com, kpsingh@chromium.org, shuah@kernel.org,
	rdna@fb.com, scott.branden@broadcom.com, quentin@isovalent.com,
	cneirabustos@gmail.com, jakub@cloudflare.com, mingo@redhat.com,
	rostedt@goodmis.org, acme@kernel.org, bpf@vger.kernel.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-kselftest@vger.kernel.org,
	Alan Maguire <alan.maguire@oracle.com>
Subject: [PATCH v7 bpf-next 5/8] bpf: bump iter seq size to support BTF representation of large data structures
Date: Mon, 28 Sep 2020 12:31:07 +0100	[thread overview]
Message-ID: <1601292670-1616-6-git-send-email-alan.maguire@oracle.com> (raw)
In-Reply-To: <1601292670-1616-1-git-send-email-alan.maguire@oracle.com>

BPF iter size is limited to PAGE_SIZE; if we wish to display BTF-based
representations of larger kernel data structures such as task_struct,
this will be insufficient.

Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
---
 kernel/bpf/bpf_iter.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 30833bb..8f10e30 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -88,8 +88,8 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,
 	mutex_lock(&seq->lock);
 
 	if (!seq->buf) {
-		seq->size = PAGE_SIZE;
-		seq->buf = kmalloc(seq->size, GFP_KERNEL);
+		seq->size = PAGE_SIZE << 3;
+		seq->buf = kvmalloc(seq->size, GFP_KERNEL);
 		if (!seq->buf) {
 			err = -ENOMEM;
 			goto done;
-- 
1.8.3.1


  parent reply	other threads:[~2020-09-28 11:36 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-28 11:31 [PATCH v7 bpf-next 0/8] bpf: add helpers to support BTF-based kernel data display Alan Maguire
2020-09-28 11:31 ` [PATCH v7 bpf-next 1/8] bpf: provide function to get vmlinux BTF information Alan Maguire
2020-09-28 11:31 ` [PATCH v7 bpf-next 2/8] bpf: move to generic BTF show support, apply it to seq files/strings Alan Maguire
2020-09-28 11:31 ` [PATCH v7 bpf-next 3/8] bpf: add bpf_snprintf_btf helper Alan Maguire
2020-09-28 11:31 ` [PATCH v7 bpf-next 4/8] selftests/bpf: add bpf_snprintf_btf helper tests Alan Maguire
2020-09-29  8:50   ` Daniel Borkmann
2020-09-28 11:31 ` Alan Maguire [this message]
2020-09-28 11:31 ` [PATCH v7 bpf-next 6/8] selftests/bpf: fix overflow tests to reflect iter size increase Alan Maguire
2020-09-28 11:31 ` [PATCH v7 bpf-next 7/8] bpf: add bpf_seq_printf_btf helper Alan Maguire
2020-09-28 11:31 ` [PATCH v7 bpf-next 8/8] selftests/bpf: add test for " Alan Maguire
2020-09-29  4:42   ` Andrii Nakryiko
2020-09-29  1:41 ` [PATCH v7 bpf-next 0/8] bpf: add helpers to support BTF-based kernel data display Alexei Starovoitov

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